I haven't had a bad experience with any card in my sig. BoA was a pain to scrape out my rewards during the PC process, but in the end they honored their end.
CapOne was a pain to open the card, but that was my own fault. I attempted to guess my account number from the welcome letter... many times 
I'd say my personal favorites are Barclay and Chase so far. Chase is my lowest limit, but I use AARP the most. Barclay has the best rewards structure.
CapOne was pretty awesome in that I've charged ~$500, returned a 7 dollar item (thus going under my $500 for the bonus), but was still able to keep the signup bonus.
BoA is pretty cool with the BBR card and the Preferred rewards program.
Amex is Amex. They're my go-to gas card and my go-to Costco card. Unfortunately that will all change. Hopefully they come out with a new product offering to fill a void, because they have been responsive to my requests and I love their business model. Unfortunately, none of their current cards would do me much good. Glad to have established my MSD though
Least favorite: Citi. I would be all over the Double Cash train right now if they would have extended the targeted $200 signup bonus offer to me. Unfortunately, the CSR processing my potential app said that the offer wasn't available for me. Oh well, guess Citi doesn't want my business. May have to PC my Costco card before Citi takes over unless they can give me a 3%+ on Costco gas.
Favorites: American Express - They actually extended me credit while still having a few baddies on my reports and scores in the mid-600's. When I applied for the Gold Delta SkyMiles card, the signup offer was 30K miles for $1,000 in 3 months. I met the spend requirement in the first month and saw they actually honored a newer offer by rewarding me with 35K miles. Pretty excited about that. Didn't even have to ask for it or anything. Oh, and their website / mobile app is fantastic. I've been moving a lot of money through the Gold Delta card while I PIF, but I hope to never trigger a FR.
Capital One - They extended me unsecured credit before anyone else would. I initially opened a $200 secured card with them and applied for the QS1 a month after receiving the secured card. They approved me for a $300CL on the QS1 and enrolled me in credit steps. Once I graduated through credit steps after 5 months, they gave CLI's to both of my cards and I now have a $500CL on each card. My experience with them has been great so far. I've only had to call customer service once when my original secured card was lost in the mail, but the CSR was extremely friendly.
Least Favorite: Credit One - While they offered a $300 unsecured CL, their interest rates are high (mine was 23.9%) and they have absolutely no grace period. After finding this out by thouroughly reading the Cardmember Agreement when the card arrived, I never even used the card and canceled it before the one year mark to avoid their silly monthly / annual fees. They even gave me a $100 CLI after having the card for a month, but I still never touched it.
Capital Bank / OpenSky - This secured card isn't too bad. It reports as unsecured and the interest rate isn't horrible at 17.45% with a pretty standard $29 AF. Thing is, this card has no opportunity whatsoever to grow with you. There are no unsecured CLI's and there are no graduations to better or unsecured cards through this bank. Their website is extremely cheap and antiquated and they hold your payments for up to five business days. While having this card at a $200 secured CL caused my scores to jump over 20 points, it was still a mediocre account at best.
Favorites
1. BoA: in 2007, issued me the only fixed-rate card that I still have open, so they take first place in my book.
2. FNBO: excellent targeted APR promotions for purchases and BT, approved me for their recent 6.25% V card offering
3. Barclays: took a chance on me and approved me for their excellent 8.00% V card in 2013.
4. Citi: approved me for cards with exceptional APR rates (cards sadly since closed, by them), gave me highest individual revolving CL at ~$25,000. Excellent low APR rates.
5. Discover: my very first credit card.
Least Favorites
1. SunTrust: attempted rate jack, they closed account after me declining.
2. U.S. Bank: high interest rates, also closed account after I declined a rate jack.
3. Chase: once my lowest-rate card (P+1.65%), rate-jacked me and so I had to close account. Subsequent APRs have been the highest ever, among my cards.
4. Amex (not the Amex card network, but the card issuer themself): never experienced the great customer service that others have quoted, not impressed with product line up or APRs.
ETA - 5. CapOne: low/unusable CLs, poor customer service, refusal to remove AF...ruined what could have otherwise been a great card, for me.
