Never noticed any aircraft in the sea but there are a few lodged in buildings. But generally, I find it plays nice with most third-party airport scenery — it really is just the odd aircraft misplaced, and you’ll barely notice it anyway as you tootle around an airport. One thing I do find irritating is Emirates SkyCargo’s habit of showing up at pax gates but, again, something you notice very infrequently. Some models are, however, better than others — but as long as you don’t go around inspecting in great detail, most look really good at the distances pilots generally view other aircraft at.
I got it in the last MP sale, for just over GP£8; but even at full price (just over GB£12 I think) it’s a good product that injects some immersion into the sim on a global level. They seem to be continually increasing the number of airports it’s effective at, as I’ve recently noticed airliners in places not listed in the promo material (and they’re not statics included with the scenery). Much better for Xbox users, though, as PC has FSLTL and FS Traffic.
Re performance, the only airport I’ve noticed it hits is IniBuilds’ KLAX, but that place does seem to have way more statics than anywhere else.