I've been a Leica Q user for a decade and in that time, Leica have shown a singular lack of imagination or any interest in providing a proper grip for the camera over the Q, Q2 and Q3 generations.
The form factor of the camera has remained largely unchanged. It isn't particularly ergonomic and has never had sufficient contouring on the body to give confidence as to the security of the camera in hand. One of the things that I have always appreciated about my Nikon pro bodies is the ergonomics and attention to detail in surface texture which really improved with the D3 almost 20 years ago. No surprise really when you consider that Giorgetto Giugiaro was behind the design and subsequent iterations of D and Z series have built on his work.
If you're a Leica owner, chances are you will have heard of Helium Design Lab but if you haven't, they're a niche design studio specialising in camera accessories, notably for Leica cameras. Helium was co-founded by Ed Palisoc and Hugh Brownstone - an architect and photographer respectively.
I invested in one of their products, the He3 - a CNC-machined aluminium grip with integrated Apple AirTag compatibility. I use the word invest deliberately. Even by Leica's pricing standards, this is an expensive item. Having said that, it reflects small batch production at the highest quality standards and is a thoughtful and well resolved design.
Leica do offer a selection of ergonomic solutions to address this design issue in the form of a thumb support and a wireless charging hand grip which ultimately needs the finger loop or some form of wrist strap. Despite having these options, you are still unable to access the SD card and battery. Leica solved this with the M series - the M11 hand grip is great so why not just reproduce this for the Q series? Is it that inconceivable that a Q user might want to change out a battery in the field?

There are a multitude of after market options at different price points, all from credible manufacturers like Really Right Stuff and other brands that I've heard positive things about but don't have any direct experience of having used. Companies such as IDSworks or JJC.
Build Quality
In a word, exceptional. It feels OEM which is probably the greatest compliment that I can pay. I've often been disappointed with after market accessories produced by niche manufacturers where it's evident that they've worked to a retail price point with all the compromises that brings. There are no such compromises with the He3.
The He3 is fabricated from CNC'd high grade aluminium (6061-T6) which is the highest quality suitable for this application. Fit and finish is impeccable and the tolerances to remove the battery and open the SD card gate were my first check - they were millimetre perfect. The high density EVA padding is the only other material finish on the grip - this is designed to protect contact surfaces on the camera - this is neatly integrated and perfectly finished.
I joined the Discord group after I placed my deposit and Ed was entirely transparent in sharing production progress photographs which was not only interesting but reassuring when you see the consideration that goes into ensuring production quality standards.
Features
Access to battery and memory card without the need to remove the grip is a revelation and every bit as good as the M series grip. Whether this should have been gated to prevent ingress of dust and debris is a matter of debate and incremental cost.
I like the Apple AirTag feature conceptually but practically, I question the real world value of it. For a camera at this price point, you're less likely to mislay it or need to locate it in your home. In the UK, you only call the Police for a crime reference number if something is stolen which the insurance company will invariably demand. UK Police are utterly useless so the idea of sharing the location and expecting them to act on the information is laughable.
With AirTag 2 rumoured to be launching mid-2025, the form factor remains unchanged so you'll be able to pick up the original AirTag for a better price or the newer model with more precise location accuracy. I'd rather have the feature than not and it adds a nominal amount of additional weight but I think the worth of it is overhyped.
One of the components of the grip is the modular thumb grip attachment - it frees the hot shoe for use which may or may not be relevant to your workflow. I use a Profoto Connect Pro wireless trigger whereas the Leica thumb grip requires the camera hot shoe as a mounting point. I actually prefer the shape of the Leica thumb grip to the He3 version but when I'm using the hot shoe, the He3 is my only option. I much prefer the logic of having an attachment point on the grip versus the hot shoe - if you have a mishap, damaging the hot shoe and potentially component circuitry doesn't bear thinking about.
The He3 works well with the ecosystem of accessories that most users have - Arca-Swiss mount compatible and it also works with Peak Design capture clips and tripod without the need for further adapter plates. There is also an additional screw mount and bottom anchor lug allowing for supplemental strap configurations and for mounting accessories i.e. SmallRig mic if you use your Q for video. The Leica finger loop still works but the mount position isn't in the same place and is less comfortable for it. I find it isn't as forgiving and perhaps this isn't a problem if you're using a wrist strap but it requires much more deliberate positioning and doesn't offer the range of adjustment.
The product arrived in a tamper proof tube and the grip was mounted to a floating cardboard base. It showed a similar level of consideration to the product itself. Sadly though, the gorilla in UK customs who was incapable of reading the instructions savaged the packaging so the unboxing experience was spoilt and felt like an exercise in salvage and hope. Fortunately, they hadn't damaged the grip but I was still left smarting over the £92 import duty.
Negatives
The price point. It's easy to complain about this but reframed, it's nearly 10% of the value of the camera so will likely have a bearing on the decision to purchase. As long as Leica don't make it obsolete by changing the Q4 layout like they did with the Q2 to Q3, you'll be able to amortise the investment over a longer term. I still use the Leica finger loop I bought in 2015 - a clean with mild soap and water on occasion and it looks like new. It's £105 now so if we take current values, that's less than £1 a month...
I actually don't like the thumb grip shape on the He3, I prefer the more pronounced edges of Leica's product and actually just use the cover plate versus the thumb grip on the He3. If I am using the Profoto trigger, I add the thumb grip as it improves handling but ergonomically, it doesn't work for me but being able to configure to my preference is invaluable.
I'd prefer a hinged cover over the base in the way the Leica M11 grip functions - it keeps debris out of the base of the grip and while I like the skeletonised design, I can see that it'll require cleaning over time. I suspect the inclusion of this would increase the cost of materials and design complexity and would no doubt push the price up further. I can live with the occasional cleaning task.
Conclusion
Would I recommend this product? Price excepted, yes. It's well considered and resolved design with the fabrication and build quality meeting Leica standards. It doesn't look like an after market accessory. There are some minor subjective considerations for me personally but none which detract from an outstanding product. If you can afford or justify it, buy it. You won't be disappointed.