Well its prettyt much the same as the initial - except you can get an examiner who can do renewals (not all examiners can do initials), there is no requirement to enter airways either.
I found the renewals to be more relaxed - if out of current practice you probably need to fly 1 profile to be up to scratch again - there again I am assuming you are current in flying in general rather than ME IR type stuff...if you are out of currency full stop then it may take a bit more...
You can do your class rating renewal at the same time..
Hope this helps,