In reply to Toby_W: Why is a 'glass boat not for a novice? My boat was a 'glass NDK Explorer and it concentrated the mind wonderfully when landing on rocky shores!!
Plastic boats are good as they are less fragile than 'glass boats but they are slower in the water. If you are paddling any distance (the whole point of sea kayaking) then this mounts up over time. And they may be stable but that will probably be primary stability and you need to look at secondary stability too. Can you sit your boat on its side and carve a turn? If you've raced sea kayaks before you'll probably understand stability better than I do though.
'Glass is also lighter than plastic. At the end of a long paddling day this becomes a real issue when you are trying to get the boat back onto your car roof, but then again maybe I'm just really puny!
And cheap? Sea kayaking is ridiculously expensive what with boat, paddle pfd etc etc etc. Mind you none of that matters a toss when you get 5 days of perfect paddling weather in North Uist. Just magic!