Aww it was worth a try, I tried first time and got a few access points but they were all locked lol.
Your asking me? Im a noob >.>
On average connections, you'll find it really hard to get accustomed to in the first few days. You press a button, it takes a while to register and then your character does the attack. Your using Marth? He's one of the worst characters that gets affected by lag as his game all about spacing. (am I right?) It'll feel your in practice mode at 1/4 speed.
I took a week or so to get used to the bloody lag, I thought I could pull off those crazy combo's I do offline, but then again... CPU's don't DI >.>
Well to answer your question, online feels alot different than offline. I think it helps a little though, it makes you think what to do next and not get punished by it instead of throwing attacks hoping you get lucky.
Am I good at it? Nah...
I gotta go now, 3.41am lol, Im away to sleep.