Just FYI, I'd proceed cautiously with the company boarder is using. They're one of the ones I'm checking out as well, but... well, I'll wait to publish my analysis of all of them, but, just be cautious. :)
There's a reason why I'm not jumping into recommending a bunch of other potential companies.
One reason for this, FWIW, is
1) Higher risk of getting a card shut down.
2) Any cards you use with another company can't be used with the current recommendation later.
Or, if you unenroll any cards from the current company to use with another tradeline company, you can't re-enroll them later (you can temporarily pause/take them out and reenroll them, if you don't use them with anyone else).
Essentially this is due to the verification procedures the current company uses that other companies do not. If the other companies put AUs on there that are not verified, it could lead to higher shutdowns later. Basically, the first company does not want you adding unverified AUs with other companies, potentially red flagging the card, then enrolling it with them, where when you add AUs, it then gets shut down mid-cycle, they have to refund the AU, etc. Extra hassle and cost. They want "clean" cards that haven't had potentially shady, unverified out AUs (or just AUs that they've verified).
Email customer support of the current company for more details, or PM me, and I can quote stuff from our conversations around it.