Originally Posted by John Kennett
Out of the four I know which I'd choose. Parker RIBs are streets ahead of the other three.
Humber and XS are both decent seaworthy boats though, although the attention to detail and finish on the Humbers tends to be a bit basic.
Like others have said, tell us about what you want the boat to do and then people can give you some more useful pointers.
Cross channel and continental use, non children/family orientated, towable.
Durable/tough and no frills.