i have both 401k and a roth ira. my employer matches 50% of my 401k contribution. fuck that? no thanks.
Yeah, if your employer is matching your contributions there's no way it isn't worth it.
Even ignoring that, though, a traditional 401(k) is generally more advantageous in the short term, given the immediate tax benefit, than a Roth IRA, where the benefit is only upon withdrawal. In Canada we have analogous tax-sheltered accounts (RRSP = traditional 401(k), TFSA = Roth IRA) and I'll only add money to the TFSA (other than short-term cash holding) if and when my RRSP contributions are maxed out.