Best 401(k) Provider

Would anyone care to offer opinions as to the best 401(k) provider for smaller technology startups? We are considering Fidelity, CUNA, and Schwab and leaning Fidelity due to the lower cost and good reputation. But I don't know if their cookie-cutter plan (no profit sharing, no after-tax contributions) is likely to feel restrictive soon. The other plans seem to cost more and be more customizable.