I use it religiously, (Because I'm too cheap to shell out the bucks for Real Flight).

I find its in the air flight characteristics close enough for use as a casual flight sim, or for helping to master the basics. If you want to just play around and cant afford / don't want to spend the $$ for a good sim this one is great. Graphics aren't so great by todays standards but its passable. If you are looking for basic handling practice this is good for that as well, you get to learn coordination and reverse direction control using it. Just don't go trying to use it to learn to fly without an instructor, but then these kind folks here will tell you that about any flight sim.

I don't think its good enough to practice 3D stuff but then I am not good enough to consider that anyhow.

I am a student pilot, with 3 actually flights under my belt since my return to the hobby. (Quit 5+ years a go out of frustration before I ever made a landing)
I started using the FMS last fall, and now that I have been getting out on occasion, (Read 3 full flights under my belt) My instructor tells me I will be solo'ed in no time, I have my first landing down, not a grease the runway but no bounce to it. Only bad side of that landing was I was aiming for the paved runway and ended up 10 feet left on the grass strip that sidelines the paved runway for those who want grass to land on.

I fly the Pitts model that came with it, most of the trainers are 3Ch and my real trainer is 4. The Pitts is a squirrelly little devil of a Biplane that loves to tip stall, but I found it perfect for teaching me to react correctly to such things as tip stalls. It don't land so good, glides in using the whole runway up on approach from a mile out LOL! (But then I don't think you'll find a sim that is good at landing practice other than for basic line up practice.)