While I do NOT advise letting Shellac go this long and I know it doesn't look great........
This one lasted AAGES. My client works at an electronic's store and has to move stock sometimes and some large boxes.. so she's in the storage area a great deal.
Anyhow... this is how long Shellac CAN last. The two 'stained' fingers is because she tried to use 'non-acetone' remover from the pharmacy to get it off LOL
As for the other products similar to Shellac (but not the same);
I've tried several brands so far (although, haven't tried gelish or gelez so can't comment on those).
My findings have been that they are either one or all of the following:
A) thicker and LOOK thicker on the nail more like an NNO of gel
B) they don't last as long
C) they require buffing before and after
D) the colours are 'streaky'
E) they don't have the same mirror-shine.
So, for my money, I'm sticking with Shellac for now. As much as it's a pain in the butt for me to get my hands on because my usual Distributor doesn't carry it, the satisfaction of my clients makes it worth the aggravation.