1. Keep it in the traditional account...not a bad choice. Invest starting now in a Roth option if your employer offers the option. It is not a bad thing to have some of your retirement in both.
2. If you have to switch, do it in yearly increments. Smaller amounts may not put you into a higher tax bracket.
3. If the market takes a plunge, you can recharactorize at a lower amount...less tax.

There are also variable such as age, current income level, future income level, retirment income, etc.