I have an 2005 Avon Adventure 4m with a 50HP Mercury 4 stroke. Its a great little package and it suits my needs which are primarily cheap to run, easy to tow, easy to work with, can launch on a sandy flat beach and fast.
The build quality I feel is good although others on here appear to have differing opinions on that but I can honestly say I have never had any problems with the hull. I seem to remember somebody having issues with gel cracks on the hull? Mines fine.
Bad points are that if the water becomes even slightly choppy then you're in for a bumpy ride almost to the point where you have to just troll home. Most have 4 strokes fitted which is fine but I have to admit a 50HP motor is very heavy for the little boat and as such take offs will be very bow high. I fitted dole fins which helped a lot but the best, and cheapest, option I found was to put 40/35KG's of sand in the FWD locker.
I also reduced the prop angle from 15 to 13 which reduced my top speed by a little but helped keep the performance good when loaded with a few people on board.
One thing I really do not like and have looked into changing is the seating arrangement on the de-luxe model. It comes with the Outhill side by side seats which means it is difficult for passengers to hold on if the ride gets lively. Also means putting passenger weight forward is difficult etc as they will just need to sit on the tubes. I think 3 people is the max for comfort really otherwise it gets a little cramped.
The best thing about this great little boat is you can run around for hours and 25 ltrs of fuel lasts ages - all day if just messing around. I went from Crow point (North Devon) to Lundy Island and back which was around 28miles and still had enough fuel to last for 30mins of messing around in the estuary.
You just need to remember its no Searider but then again its much better looking
Have fun - thats what they were designed for - nothing more.
I noticed you said you were looking for a 2006/7 4m? I thought the newer models were 410 not 4? I may be wrong.
Pete M has a great Adventure 4m with a Yam 50 on - give him a bell and ask him what he thinks. I think he has used his on some trips with some bigger boats for back up/company. I aim on keeping mine for a long time especially since fuel became so expensive.
Best of luck with your search. There was one recently on ebay but vanished halfway though the listing - guess it was sold outside ebay?