I have the 6.3 metre Northcraft and it handles really well, gets on the plane easily and Iíve been very impressed by itís seakeeping. It feels very safe and itís an easy boat to drive. Even with a 115hp fitted the speed is reasonable too; had it up to 37 knots with 2 on board and 90 litres of fuel. Northcraft used to race with this hull so I guess you would expect decent performance.
In my opinion, having seen 3 boats in construction at the factory and owned mine for two seasons, Northcrafts are very solid but the finish could be a little better. But then you should not expect Roll Royce quality when paying Skoda prices. I have not had any problems at all with the tubes losing air.
When my RIB was being built I found the company extremely helpful and willing to do any amount of customisationÖ And you do get a LOT of boat for your money. They are, however, a very small operation (3 people there at the time I bought my RIB) and getting hold of them can be problematic. I tended to phone late in the day otherwise they where always busy in the workshop.
They used to have a fairly decent web site (not the one mentioned in this thread) but it seems to have disappeared.
I believe the 6.3m hull is an old Fletcher design, but I could be wrong on this.