Maybe a noob question, but now that homebrew works on 1.5, is it worthwhile upgrading my 1.0? Does it bring any aditional features that are worth having?
There's only one reason to upgrade to 1.50, and that's if you want to be able to play a UMD game that requires it. If you're not interested in that, don't upgrade. Not only will it make it so you have to use the exploit to run homebrew, but it will lower the value of your PSP. As a 1.0 owner you could name your own price if you ever decided to sell it.
When you upgrade, does one get to choose how far to upgrade?
It'd suck pretty hard if you went straight to 1.51/2 and never got the chance to get off at 1.5
yes, just download the 1.5 updater from the internet and put it in your UPDATE folder, DO NOT use network update from your PSP settings menu this will take you straight to 1.52