I hate to admit it, but I've always had a strange fascination with top-break revolvers. I've owned several, with varying degrees of disappointment over the years.
Four Webleys, an Enfield, a couple of H&R 999s, a 925, several S&W pocket guns and copies in from near-new to junk condition, a Navy Arms in .45 Colt, and a Performance Center-made S&W #3 Schofield.
Besides the various Italian Schofield and Russian replicas, the only example being made currently that I can think of is the 999.
My experiences have pretty much been in line with what's already been said. Converted .455 Webleys are only middlin' accurate at best, and use with .45 ACP hardball will loosen them up in fairly short order. The DAO Enfield has to have the worst trigger pull ever. The .380/200 (.38 S&W) Webleys are fun, but US factory loads will print so low that you might have to use two targets to keep them on paper. Or file the front sight down to a nub. Some of the little pocket guns will surprise you, but many of them are only safe to shoot with mild BP loads. Some of the Spanish, Belgian, and even American copies of the little Smiths probably shouldn't be fired at all, even in pristine shape.
The Uberti-made #3s are a hoot, but I'd stick to "Cowboy" loads in either .45 Colt or S&W. The Russian looks strange, but is capable of superb accuracy with the right load. H&R 999s with either 4 or 6" barrels make great utility/knock-around guns. Can be pretty accurate with ammo they like, but won't scare any K-22s or Rugers. The single-shot target pistols H&R made 'way back then are another thing altogether, but expensive and hard to find.
If you want a top-break primarily for nostalgia and fun, I'd go with a 999. Cheap to buy, lots of nice used ones even cheaper, cheap to shoot and hard to break or wear out. A Navy in .38 Spl. should be fun and quite safe with standard pressure loads. Might even surprise you with its accuracy with the right ammo. Expensive, but about the only CF made in any caliber. If you want a Webley, I'd look for a nice Mk. VI in .380/200. Lots of them still around so a good one won't bust your wallet.