I think the answer is quite simple, if you want or need all the new features and don't mind a bit of a learning curve to get them go for P5 (if you realy count the individuals who are posting major instability problems you'll find the number is not that large, it just seems so becouse the same people post regularly of their problems. thats not to say that there arent real hardware compatability issues with this program, just that it does'nt seem to affect most people, I for one have not yet had one crash or major usability issue.)if you don't need the new features and like the simplisity of P4 by all means stick with it it is a great program. and so many new features can slow a system down some. I compare it to the difference between photoshop and paint shop pro, photoshop is so much more versitile and complex. it loads slower and many of the features work slower but if you need those features you deal with it. for my use paint shop pro does the job, I use Photoshop at work but Ill never put it on my home computer.