UVBeast are all horribly marked up in price, you get equal/better performance with Convoy, and for cheaper! Haven't heard of the other brands but doubt they compare well to the Convoy offerings.
What do you want to use it for? And just short bursts, or for longer periods like night hikes? Distance you hope to spot things?
The S2+ is a great value, either with the rubber button or the metal button, and the standard Nichia is good as is the Seoul Viosys or LG that Simon has offered (not sure what all he has in the store currently but they are all pretty comparable). He has a triple as well, which may be a better choice, and he has a C8 version (M21A with 21700 cell size) with a really powerful emitter and a great driver that will allow longer run times - it’s intense, though.
The UV Beast and Alonefire lights are….they work. Higher prices and lower quality combined when compared to Convoy models, but they’re easily available and usually quickly on amazon. Sofirn and Lumintop have some smaller pocket AA/14500 models that are ok, just limited in output and run times.
Most of these are 365nm wavelength which is generally what you want, and definitely try to get something with the filter glass (installed or separately that you can swap out). Sometimes the more common 395nm or uncommon 380nm might suit you better depending on what you need from the light.
UV emitters are hungry for voltage and also sensitive to heat, so many will start to dim fairly quickly - want to use good cells that don’t suffer from voltage sag as much and/or have a spare cell on hand for longer use. Also generally not recommended to run them for long periods where they are running warm or hot, just to prolong the emitter life as apparently all of these seem to suffer what we’d call early failures compared to the usual robust white emitters. All of mine have done well, even the S2+ that has seen a ton of use, but UV emitters are just kinda fragile in comparison.
Almost no reason to buy the old school bi-axial led’s at this point, other than working ok with alkaline cells in unison for low output cheap lights.
We have issues here in the US with a certain patent, so Simon’s (and some others’) UV lights don’t always show up, or they do and we can’t purchase them. I’ve found it easiest to see what’s there by doing a search for “365nm” in his store, or via google. Things aren’t always categorized right.
I haven’t gotten the Convoy… I can’t say I use my UV lights that often… it’s fun to have one in your pocket and shine it on low power indoors to impress your kid :).