Generally, a 401k doesn't offer very good investment choices as the plan provider's customer is your employer and not you, your employer want's the lowest cost to him so the plan provider makes their money off the high fees and loads of the mutual funds offered to you in the 401k. Some employers will pay the plan provider more in order to offer their employees a better selection of mutual funds but this is the exception not the rule. However the employer's match is free money, basically doubling your investment right off the bat so even though the investment choices are poor, investing up to the employer's match is a good decision as the match guarantees a decent return.
After you've met the employer's match, you should consider maxing out your IRA which typically offers much better investment choices. Brokerage IRA accounts are available and they offer all the investment choices that you would have with a brokerage account. You still have to make sound investment choices but if you're willing to put the time and effort into it, you should be able to do better with an IRA than a 401k. The Roth only has an advantage over the standard IRA early in your career when you're underpaid, if your career is going well, you should switch contributions to a traditional IRA while keeping your Roth. The contribution limit of the IRA's is only $5,000 a year so after you've maxed out your IRA's, you go back to adding contributions to your 401k. Even though the investment choices are likely to be bad, tax deferred is still better than taxable investing. If you've maxed out both your IRA contribution limit of $5k a year and your 401k contribution limit of $16.5k a year then contribute your excess to a Brokerage account. Try to hold municipal bonds and long term buy and hold growth stocks in your Brokerage account rather than anything producing taxable income, keep your portfolio balance point inside your tax shelters. That way, you'll be effectively extending your tax shelter as much as possible.
There are two vesting concepts, one is that if you manage to hold the job for 4 years, then perhaps your job is more secure, the other, that of your vesting in the company match starts with when the match is made so if you wait 4 years to start contributing, that just means you won't be vested for 8 years. You should start the contributions as early as possible but only up to the match and then contribute to your IRA's. Not starting now only guarantees you won't benefit from the program.