I've never known spasm to crash, the only gripe i really have with it is that unless you add in parentheses it will process expressions from left to right, so 5+3*2 i believe will evaluate to 16 (that is, (5+3)*2). I personally love spasm, it's super fast, powerful, open source, and super tiny (my spasm executable is 124kb). Especially when you start getting into larger projects you'll really appreciate its speed
Though as has been said many times before, the most important thing, at least when you're getting started, is to get something that works. Fortunately, that's much simpler now than when many of us started back when TASM was the assembler of choice (coupled with Devpac)! Later on you'll get an idea of what features you really want and can work from there, though what will most likely happen is that you'll stick with whatever you start with
Welcome and i hope to see you stick around!