The RO is basically the same gun as the loaded models, sans front serrations and a target sight instead of a fixed novak sight, plain black front instead of tritium. Trigger pull is in the same weight range of 5-6lbs.
My RO is very accurate and had a decent trigger out of the box. Heine makes a nice fixed rear replacement (as I hate target sights, got the RO for a good price that is why I own one), it's big and ugly compared to a normal fixed sight but it's well made and works great.
As to your sight reference, only Heinie and Harrison Design offer LPA replacement sights. That is the main drawback of the RO, limited rear sight options.
Look at each gun and see which one offers the features you like the most.
I cannot speak to the Colt, as I have never owned one.
Here is mine with the Heine.