Having owned 3 different boats with different materials I can tell you that poly's ride is between alloy and fibreglass. I like the ride quality of a glass boat but you really have to be careful with the hull.
My current boat is a 4.1 poly, they only bad thing I can think about them is that it's kinda wet when the wind is blowing in the wrong direction. They are very durable and you can call the hull maintenance free, I'm not too worried if don't wash the hull after every outing. Poly boats are quite heavy compared to a tinny thus require more horsepower to push the boat, so I'd recommend getting the Max HP allowed if you're getting one.
When I was doing my research the poly best fits my budget and requirements. Oh and if you have a scratch on a poly all you need is a heatgun to mend it.
Swordy also have a 4.1m poly and I'm sure he's happy with his.
They do make a 4.5m model from memory and they have a new 4.8m model.
go to polyboatowners.com all the poly fanatics are there and they're really helpful.
If your budget can stretch further the yanks version of the poly is the triumph, they cost a lot but their finishing and layouts is something I envy. http://www.triumphboats.com/. Check out their ads in youtube and you'll see some crazy stunts they do with the triumph.
As Ross stated with your budget you have plenty options to choose from... start reading up on boats to get a better understanding of them, and also make sure you get a boat that suit your needs, so that you don't end up selling it after a few months of use. Oh make sure you get something with a steering wheel my first 2 boats were tiller steers and having a steering wheel make things a whole lot easier.
"BOAT= Bring on another thousand!" Ditto to that ! new sounders, electric motor, downriggers, new seats, deckings, carpets, etc.... it's neverending.