In Japan, as you may know, people do take care of their gear/instruments. I bought many (almost all?) stuffs second hand and never had any problem here.
It's hard to find lefty ES-335 second hand (that's the only one I found!!) and investing $3500 (it's around that price in Japan) is way too much money for just the hobbyist that I am.
Gibson's necks are well-known for snapping easily, after all, they bent it against the natural flow of the wood.
I think other manufacturers with the same angle glue 2 pieces of wood together (but I might be wrong) so a repaired Gibson neck should be as good as any other guitar if it was done properly. They also added a volute it seems and from the pictures it seems very well-done (but I'm no expert haha).
I'd be happier to buy a second hand lefty ES-335 at $2,000 if I could find one but $1,500 is more in my budget and rather tempting... But I have to say that I'm still on the fence... I've never bought a guitar with a neck repair but the worst could be to avoid the second hand one, buy a brand new one for $3500 just for it to snap on me haha... that'd be ironic.