Question:

How good is Ness? He's my third favorite character, and I was wondering if he's actually worth praticing with.

If he's your third favorite characters then play with him and have fun.  Why worry about the rest?

Any character you like is worth practicing with. in Smash Bros, it's possible to dominate with every character, Smash Bros is all about timing and forcing your opponent into a predictible path that you can intercept while ensuring that your path remains unpredictable. Taomaster has schooled my ass numerous times with Ness, and that's when I use Marth, my best character.

If you want to get into hyper competitive technical terms, then it's all pretty much up in the air right now. These are the wild west days of brawl. It hasn't been out long enough for there to be any definitive tier lists, which developed over years for melee. And even then, tier lists don't matter half as much as skill because most of us aren't good enough to push a character to their theoretical limit. I'm definitely not a super competitive player, and I've yet to meet anyone here that can just outright stomp my ass over and over again like the pros most likely could. So if you like Ness, go, play with him and get good with him and you'll be able to compete based on your skill as a player, and not based on a character's worth.

Unfortunately I'm pretty crappy at 4 player, as I'm sure you noticed.

You'd probably beat me 1 on 1 anyway, but yeah, 4 player = bad haha. 

 Ness is good if you pratice.. Who was I fighting against? They were pretty good matches too bad there was too much bad connection

i just got sonic

Aw.  What happened to the cocky, confident, "I'm gonna school you when Brawl comes out" Naznatips?

...A lot of people have stopped bragging it seems.

BTW naznatips, you haven't added me yet :( sob sob sob

As for the characters...

Good: Pit, Lucas, Sonic, Wolf, C. Falcon, Zero Suit Samus, Sheik, Ness, Snake, Lucario, Dedede

Not so good: The rest

ness is my main, and I'm good with him. once you learn his attatcks and how to pull off combos he can easily go up againt a fox or marth.