Someone (madfientist, MMM, JLCollins??) wrote a nice blog post analyzing whether you should skip your 401k simply because of the fees and/or funds available, but I can't seem to recall who it was because I can't find the post. The general point though was most of the time you will overcome the shitty options with the great tax break, as long as you don't plan to stay in the job forever.
To quantify "bad 401k fees vs. taxable", consider using the "401k vs Taxable" tab on the
case study spreadsheet.
There is a "rule of thumb" in the
Bogleheads' 401k wiki entry: ''consider investing in a taxable account if the product of the extra costs and the number of years you will stay in the plan exceeds 30%." Unfortunately the conditions under which that rule is appropriate aren't given, so
caveat user.
The Bogleheads wiki also links to
http://thefinancebuff.com/alternatives-to-a-high-cost-401k-or-403b-plan.html, from which one can access an online evaluation tool. The linked article was written in 2008, when things such as backdoor Roths weren't in use. The online evaluation tool doesn't allow one to see calculation details, but it and the case study spreadsheet match exactly for traditional 401k and taxable account calculations over a variety of inputs. Ease of use is in the eye of the beholder, so use whatever is easiest for you.