Python's are fine revolvers, but they are big collector's pieces now days which takes them out of the realm of what I consider practical. The bad part about it, they are not "rare" by any means. Any day of the week, you can find 50 or more for sale. To me it's like an artificial market.
3" are rare by any means. They did not make many. Mfg. for Lew Horton with a K prefix. Demand 50 to 100% more.
If you know what you are doing the Colt market will produce great returns honestly. Just review the comments on this thread.