I use a classical-type position, and find it generally better than having the neck nearly horizontal, as I see many others do (and as I used to do--and sometimes still do). I usually stand up, as there's generally not a footrest available.
It's very helpful to have the guitar body perpendicular to the floor. This means getting away from having to look at your fretting hand. Takes some practice, but well worth it (kinda like learning touch typing, so much easier and quicker than looking for keys, once you learn it). Roundback guitars (Ovation, etc.) are difficult to keep straight this way. And I find that many guitars with a strap peg on the heel have the peg located where the instrument tends to roll toward or away from the body. I very carefully find the balance point for the strap peg before installing it to avoid this problem.