How long is a piece of string?!
I love some and strongly dislike others...
For me, as with most things, it depends on the type of studs, the arrangement of them and the design of the bag.
Contrary to what some others have said, I actually think studded bags generally look better when the focus of the design is on the studs (but not necessarily due to their number) and for that reason, I tend to prefer studs on clutches; as I think they can look a bit overwhelming (or overwhelmed) when combined with a larger, more complex bag with handles and/or a strap and lots of other assorted hardware, like rings and zips etc..
On the whole, try as I might (because the colours are amazing!), I'm not too keen on Balenciaga Motorcycle Bags, personally. As, to me, the shape of the studs isn't particularly attractive (they remind me of doorstops! :shame: ) and they aren't enough of a focal point and look a bit half-hearted and if I don't feel they add anything to the design, I'd rather not have them there at all, TBH.
I have a Chloe Ida Clutch from S/S '06, which is gorgeous and has a 'belt' wrapped vertically around it with vintage-look studs in three different colours and finishes on it (which I absolutely adore!) and I have just bought a Chloe Elvire Clutch: