When/if employment ends, the account MUST be properly transfered to ANOTHER equivalent tax-advantaged account, or penalties (and perhaps fines), as well as possible maintenance fees will be accessed. Is it "difficult"? No not really. But you need to know those ins and out.
Really easy to do. Not a problem.
Company matches are USUALLY maxed at 1% to 3% of EMPLOYEE WAGES/INCOME. A 4 or 5 grand pre-tax contribution is unlikely as far as the max company match is concerned. Beyond maxing to the company match, MOST company 401k's carry limited investment options, AND higher than average management fees than an individual can achieve through a self-directed tax-equivalent vehicle. Not maxing to the company match is leaving money on the table. Anything beyond, is better invested through a self-directed vehicle.
If you're starting out, you should be in the lowest tax bracket that you will be for the remainder of your life. If your marginal tax rate is low, I'd only do the company match to the maximum amount that they allow -- take full advantage of that, it's free money. But beyond that, especially if you live in a state with low income tax, you're probably never going to see income taxes as low as they are now assuming that you are making median US income or higher. So in that situation, I'd prefer to pay taxes now while taxes are relatively low. Exception would be if you live in a high tax state. In that case, 401k has an advantage because you can someday move to a lower tax state before you sell and avoid the state income tax.
If you work hard, picked a good major, live within your means, and do your finances right, you should have enough investment / dividend income to always put you in the top one or two tax brackets (as they are now) even after you retire. So in that case, your tax rates at withdrawal would likely be higher than they are now. I also like the flexibility of an individual broker account over a 401k / IRA any day. Naked short options, portfolio margin, and the flexibility of moving the capital into other investments (real estate). If you like your job and want to stay in the area, you're probably better off buying a house and building equity / mortgage tax deduction over investing in stocks anyway.
I'm still contributing to a 401k, but my investments have been moved to stable value and all new money is going into stable value since Jan 2018. In hindsight, I should have switched back last December, but I think there will be a better buying opportunity coming.