I also signed up with the ING orange account, also for the bonuses, but my husband is encouraging me to switch to Vanguard. I opened up accounts for both of our kids(in our names) for the money they got since they were born. He put one in Vanguard and I put the other in ING. The rate he is getting is much better. But he didn't get a bonus. I don't think either have finance charges, and you can write checks (money market) for anything over $250. We also use Vanguard for our Emergency fund(Thank You Dave Ramsey), so if you are comfortable with online banking, switching money around is quite easy.
Vanguard has the best rate that we have found. However, if you are looking at more of a long term savings you might consider one of the mutual funds, becuase they have performed quite well this last year and beyond.
But if you need money quicker, or in lower amounts than $250, ING has actually been quite good for me.