Not to even perpetuate the resurrection of a 5 year old thread.. They are both truly great speakers. I think the term finesse applies best to 250Ti and dynamic, brute force and live applies best to L300. I think at modest or less listening levels, the 250ti is really tough to beat and I'd take it hands down over an L300. However, if my goal were above moderate SPL listening, clear winner L300. In may respects, I regret selling my 250Ti, but I truly believe I am listening now to better and more dynamic.
That's my opinion YMMV.