I have found Capital One to actually be pretty good. Capital one started my business with a $15k credit line. After maybe 6 months they bumped it up to $25k, then 6 months or so later up to $50k, all automatically.
I would put about $30-60k per month on it, even when it was at the $15k limit. I would just pay it off constantly. Now it's a lot easier with the higher limit.