I have very specific aims with 3d modelling and rendering - just to be able to illustrate designs and ideas so that prospective clients can understand what I'm waffling on about. If I was younger and less specialised I'd definitely be trying to learn 3d apps other than the ones I use now. If you need modelling skills at more than hobby level, you need to be able to use a high-end application. I don't think anyone should have loyalty to a piece of software. It's all about what suits you. Maya is pretty complicated, not to mention expensive! Most people will never get to use it. Basic skills learned in other programs (3d modelling is 3d modelling, lighting is lighting, texturing is texturing) can be carried from program to program. If you've no prospect of ever being able to afford a legitimate copy of Maya, it seems to me like you'd be better off learning the basics in cheaper programs, progressing to more expensive/flexible programs as your skill-level and purse allow.