Both L+P and UV Gel are acrylic based... it depends on the quality of the product as to the strength etc.
Deciding on which system to use on a client is dependant on their lifestyle, some clients get on with one system better than another too.
If you use a 'top end' product range (high quality) then there won't be much difference between the strength and longevity of either L+P or UV Gel.
But from what I've been reading over the last couple of years, and 'seen'.... my conclusion is whichever you do best. I've seen great results in both, and I firmly believe it's all in the technician's own skill.
Mind you, there might be the odd client for whom one product or the other is incompatible for odd reasons that aren't everyday...
But....if you are choosing between two EQUALLY QUALITY products, my opinion would whichever one you do best is the one you should do.