I had one for many years until redundancy forced me to sell it.
I loved mine, it was light, compact, pokey and well made.
I never had any issues with my grip as I think mine may have been a mk.II model (I was asked to sell one for a friend some time ago and his grip was noticeably more uncomfortable than mine ever was...)
Likewise I had no issues with the breech seal either.
Accuracy-wise, I could shoot mine as accurately as my HW45 with no-trouble, granted the gun sits somewhat higher in the hand, but this didn't seem to affect my UBC scores at the time.
The only thing that bothered me slightly (because I was inexperienced back then and didn't know any better) was the fact that the sight rail is quite high above the bore and most optical sights run out of elevation adjustment.
Personally I think they're far better than they're credited for - the airgun press weren't particulary complementry at the time or since which is ironic when I think about about the money I've wasted over the years on some of the tat which was well recieved....