OK - I'm not a huge fan (the $8.25/month annual fee is annoying) - but it's no better or worse than any other card I've had. Yes, it's a sub-prime card. I started my credit line with them at $500 (as did my wife) and we've increased that to about $1500 each over the course of a couple of years. We haven't really used the cards much, other than for a couple of subscriptions - so we haven't bothered increasing our credit lines any further.
However, what it HAS done is allowed us to get standard cards with other companies.
The annual fee is annoying - but there are few no-fee cards any longer, and at the premium credit card level, you're looking at much higher annual fees (like United club cards with $450 annual fees).
That said, it's a solid one to keep if you can handle the annual fees. If not, it's a good one to re-establish yourself until you can get to a better level card.