Best client? 2012L. Iβm a bit biased as I joined in 2012, but in my opinion itβs sort of the best of both worlds client. As a player it has all the old ROBLOX hallmarks without anything being missing, and as a developer it has pretty much everything Iβd need to make a game without major concessions needing to be made (excluding auto-indent anyway). Other clients can do these jobs better separately, but itβs both factors working together that elevates 2012L to the top in my opinion.
Worst client? 2007E (or honestly anything before like 2008L). Least features, least replayability, playing it is like youβre trying to control a dream, developing for it is like cutting off both of your armsβ¦ I donβt like it.