I have a RIA FS Tactical in .45ACP. It's a decent pistol. I got it because it was inexpensive. I also have a massaged Springfield GI model. The massaging was the result of sending it through the Springfield Custom Shop where they applied their defense package, lowered/flared the ejection port, installed a match barrel bushing, and added Novak 3-dot sights. When I got the RIA, it had an ambi-safety and a full-length guide rod, which I immediately swapped out for standard parts because a FLGR requires tools to field strip, and I think that's kinda pointless. Anyway, I took it to the range a few weeks ago (almost 10 months after buying it), along with my massaged Springfield GI.
I was shocked and disappointed at the 9-inch group I was shooting at 25 yards with the RIA, and figured it might be because I was a bit rusty. So, I broke out the Springfield, and proceeded to shoot a 3-inch group (same ammo, same distance).
When I got home from the range, I ordered a Storm Lake barrel/bushing kit and a Grieder adjustable match trigger from Brownells. Both parts were drop-ins requiring absolutely no fitting at all. Went back to the range, and the first two shots out of the pistol produced a ragged hole bullseye at 10 yards. Just - wow.
While I had the pistol disassembled for trigger installation, I noticed that the sear had two pretty deep diagonal machining grooves in it. They were so deep that I didn't think the pistol would be safe if I stoned the sear, so my next mod is to replace the sear/disconnector/hammer. However, base on how the pistol is performing right now, I can demote the priority of that adjustment pretty low on my list of "things I want to do to my guns".
For what it's worth, it's very possible that leaving the FLGR on the pistol may have improved the out-of-the-box accuracy, I'd rather have a pistol that can be field stripped without having to worry about whether or not I have the tool on-hand. At the same time, the Storm Lake barrel is most definitely a reasonable purchase for anyone that wants a little more accuracy out of their pistol.
Final note: The Springfield with mods has cost me about $950 (not including extra magazines). Yes, it's "just a GI model, and yes, I realize that I put almost $500 into the pistol that I will probably never be able to recoup if I were to sell it. Compare that cost to the RIA, which has cost me about $600 (including mods), and is even more accurate than the Springfield at this point. Customizing an RIA to any great extent is akin to polishing a turd, especially if you're thinking you're gonna get your money back on your investment. I don't buy my guns with an eye toward resale value or what they look like. I simply want them to serve their purpose to the best extent possible. If that means throwing a bit of extra money at them, so be it.
Oh yeah - when/if you get an RIA, be prepared to get new grips. The ones that come on them are smooth and perfectly useless. I bought plain checkered ones for mine.