If you have to choose one make it a fixed set! also if you decide to go only for a portable then please make sure you get an extendable emergency VHF ariel
re makes then I'd rather catch the clap again than buy another Icom fixed set, but to be honest I have three Icom portables and only one of them has failed so far. I certainly wouldn't advise buying a cheap XM portable as they are not at all waterproof.
The Standard range of portables seems to be reckoned by a few people
Go and buy practical boat owner and look through the Ads which will give you an idea of how much you shoulkd be paying for your choice!
if you want to know how to use it then you can go on a course or get one of these http://www.amberleymarine.co.uk/html/vhf_-_dsc.html