Well, I'll start with the Colt. It is a very neat looking gun. It also doesnt have the problem the Remmys do with spent caps falling and jamming it up. However, it's much easier to work on once you get it apart. Its biggest advantage to me is probably the balance and feel. It just feels better in my hand.
However, the Remmy isn't exactly ugly. It has also been much more reliable than my Colt, minus the falling cap issue. I also find that i can be much more accurate with it compared to Colts. Perhaps best of all is the quick and easy disassembly, especially the cylinder removal. When reenacting it is very nice to be able to quickly switch to a different cylinder.
Overall, I prefer the Remington. Its just a much better, more reliable design than the loose fitting Colts, and more conveniant in almost every way.