I use a 2055(80oz, nonwaterproof) version on my basher TXT. They don't turn the tires at a dead stop but they aren't slow, infact they're faster than the very popular hitec 645. The plastic may or may not be a problem depending on what servo saver you have and what you want it to do, i.e. crawling hardcore jumping/racing. They aren't near being the best choice but they aren't the worst and if you can get them cheap like I did($10 for 2) they're worth it for just messing around. Like I said mine isn't the waterproof version but I did waterproof it.
The towerpro 995 has crazy torque but is slow and doesn't center properly. I use one in my 2.2 Rubicon scaler and it's perfect for that. I'm on my second one but only because I mistreat that truck, it has been in mud, sand. and underwater(even in the ocean) before the servo housing got warped(common in this version) and even that took about 6 months of hard running.
There are newer versions of the towerpros, 945, 946R, but I have no experience with them but I can only assume they're better.