The two most dominant brands on the market are CR Speed and Ghost. Safariland, Bianchi, Arredondo, Limcat and a few others trails behind, but all essentially should work just as well. If anything, they would be a bit more unique since they won't be just like every other CRS/Ghost wearing shooter out there.
It comes down to personal preference which one you want to go with, but there are some basic differences between the platforms. I only have experience with CRS and Ghost. The basic pros/cons of both:
CR Speed Pros:- Multi-Platform System, can accept Glock, 1911, 2011, Sig and more with one holster.
- Ambidextrous. Can switch to left side or right side by swapping a few parts
- Can adjust barrel rest platform to fit different length pistols
CR Speed Cons:- Is not quickly adjustable. If you need to change pistol platforms (ie from 1911 to Glock), from right side to left side, or barrel platform height; it can not be done on the fly. Tools are required, and it's ideal to do it with the entire belt rig off your body.
- Fairly large size, makes storage/transport a bit more difficult when attached to the belt.
Ghost Pros:- Multi-division capable. This holster does not have a barrel rest platform, so it's extremely easy to change from an Open Division compensated pistol to a Standard Division pistol without having to make any changes. This is great for shooters who will compete in multiple divisions. Also great for backup if your Open Division pistol goes down and your only backup is a Standard Division pistol of the same platform
- Very small size, easier for storage and transport
- Very ergonomic and fast acting trigger guard lock system. When used properly, it is next to impossible to knock the pistol out of the holster.
Ghost Cons:- Not multi platform capable. You must purchase a specific holster for a specific platform. For example, you must buy one for Glock, and another one for a 2011. You can not properly fit one to the other.
- Not ambidextrous. You must purchase a specific side, you can not swap sides like CR Speed
The magazine pouch brands also have their own pros and cons, but you may be able to see these just by looking at them. I personally run a mix of CR Speed and Ghost holsters, depending on my loadout and requirements. However, I do lean a bit more towards CR Speed mag pouches.
As far as replicas are concerned, I'm only aware of CRS, Ghost and Limcat replicas on the market.
The best thing to do is to actually make it out to an event and check out people's gear, ask them about it and get opinions.