Yes they are great rifles. I have heard that Marlin has put out some clunkers in recent years but I can't say if that applies to the 336. Check out the Marlinowners board and see what they are saying. They have a forum dedicated to the 336 I think.
I really like levers for still hunting, where shots will be close and I may get a shot at a moving deer. Mine have peep sights and are very handy. For a treestand, regardless of range, I prefer a scoped gun for precision shooting. Usually I'm shooting at a still or slowly moving deer.