Also - and I realise this might be contentious - but I'd suggest one that takes normal batteries. Mine takes 4× AAA.
With Eneloops (or similar low-self-discharge rechargeables), can have a 2nd set that gets you back up and running in under 30 seconds, and if you get really stuck they're sold in every corner store in the world (heck, throw a pack of Li-FeS2 batteries in the emergency kit, 20 year shelf life).
No worrying about having the right charger cable (commonly a Micro USB, something I don't tend to carry anymore), or remembering to charge the thing lest it go flat right in the middle of what you need to do.
You just know that if they did have a support email address, it'd just reply with "💩".