Jordan,
Just so you know, the Rancho RSX and Monroe Reflex are the exact same shock. Both are made by the parent company, Tenneco; and sold under two different brands. If you're deciding between those two shocks, it will probably boil down to the best deal you can find.
I have the Rancho RSX's. If I had to do it over again, I'd have probably bought the Monroe Reflex's. The RSX has a red rubber boot that you have to put on over the shock during install, and it's a pain in the @$$. The Reflex doesn't have a boot, so the install would be much easier.
Tip: However, if you do purchase a shock with a rubber boot, use a little bit of dishwashing soap as a lubricant, and the boot will go on a little easier.
I'm sure you'll get recommendations from members here for many different replacement shocks. Anything is an improvement over the stock shocks, so you can't go wrong no matter which shock you choose.