Eric,
The 50 gallon Fimco from TSC is the sprayer I have. It's probably 4 or 5 years old. I bought the PTO pump they recommended, which is the HyPro 6500. It pumps 9.7 gpm, which is more than enough for the sprayer.
This is the only sprayer I've used, so my breadth of experience is limited. However, the Fimco seems to work well. It is used to spray a couple acres 2-3 times a year. It's been reliable.
Three drawbacks for me:
1. When a tree trunk catches the 10' long boom, sometimes the nozzle on the end will be pulled off as the boom arm folds and brushes past the trunk. No big deal, but I have to stop and clip it back in place. I haven't found a way to keep that from happening.
2. Some sprayers come with a diverter valve and a handheld sprayer wand attachment. The Fimco did not. Seems like a cool option. My preference, though, is to load the last gallon or so into a separate hand pump sprayer and walk to the spots the larger sprayer can't get to.
3. The sprayer is not set-up to easily drain left-over liquid. I like to have a little left over for hand spraying. It's not too hard to splice fittings into the rubber hoses underneath the sprayer to make a drain hose. That's what I did this Spring. I mounted a brass (corrosion resistant?) water faucet to the metal sprayer frame and connected the drain hose to it. Now, at least, I can drain the extra chemical solution and not get it all over myself.
Overall, I'm pretty satisfied with the sprayer.
OkieG