I voted for it being fine. The website isn't too bad, although I hate that sideways overshooting in the Maemo browser while scrolling down.
So far I had no problems with payments. For being beta it's OK. Hopefully the final thing will get more polish, though.
I remember Android forums where people where complaining at the payment system of the Android market (Google Checkout), which didn't work for many people either. So I guess all stores have some trouble with payment. Maybe even the fruit shop.
The big major advantage of Ovi store compared to the application manager is that it can sort apps by age.

Now the shop only needs more apps.