While Colt DA revolvers are great there are problems. First off, it's been a very long time since they were discontinued so parts are either very rare or not available. Even worse there are very few gunsmiths who know how to work on colts if they need repairs and parts can be found. This is why I recommend Ruger or S&W DA revolvers.Just my 2 cents... I would definitely at least look at a Colt Python. There are many available in "like new" condition and you will have a truly fine collectible to enjoy for generations to come. Whatever you pay, they will be worth more as time passes.
For your stated uses, I would not go with less than a 4-inch barrel. Shorter barrels are handier for conceled carry, but generally result in more recoil, more muzzle blast and less accuracy. The longer 6-inch barrel has some advantages in wringing the very best performance out of a .357 cartridge, but I find the 4-inch generally balances better in my hand. YMMV.I am looking to buy a quality 357 magnum revolver! This handgun would be used for both home defense and shooting at the range!