Bought bike in Dec, touch wood yet to have a problem in a trial. Completed every trial or practice. To be fair had a couple of issues, but sorted by Pennine and Ossa under warrenty. Recently changed to map 8, had to learn how to start it again, but will start within 3 kicks from cold every week. For a new bike out of the box, Ossa have done a great job.
The 280 is very smooth,with lots grip, wish I knew how to use it all. Last bike was a GG 250 Raga with a flywheel weight, which I thought was as good as it gets, one test ride on the Ossa changed that. The feel of the bike is great, very balanced and with the Ohlins shock no upgrades needed. The fuel injection removes the mid range power surge, which is always there on all the other 2 strokes I have tried. This is not a good thing to have for me, big steps are for watching others attempt. I bought a Beta 4 stroke and tried it for over a year, this is the best comprises so far.
My only issue with Ossa is the lack of clothing to go with the brand. Is it worth the extra, have a go on one is the only advice I can give.