seems you have done your research and now are confronted with, how much money should i spend. This is going to be what your willing to live without. My bet is the more expensive players will give you better picture quality maybe features. What do you require as a min? this should answer your question.
As for keeping your Oppo, well it is getting on in years and mechanical systems will fail eventually.
If it was me I'd buy the best you can afford and hope it out lasts your system until you need something else down the road as formats change, new tech comes available, etc.