I've been using my cartotanks for over a year. Personally, I find that they provide excellent flavor production, are reliable and consistant, and quite durable for out-and-about use.
I've been using a couple of AGA-T2's for about 4 months now. Much larger learning curve than the cartotanks. Can be frustrating and unreliable unless you are the type who can build a great wick and coil 100% of the time. When working optimally, there's not a better
juice delivery attachment. But, I have found these to be fiddly and time consuming, unlike the cartotanks. Most Genesis-type RBAs will leak juice by the nature of their design if not kept upright, so they are not ideal setups for out-and-about use.
If you are having issues with just a cartotank, I wonder if you're ready for an RBA. Should you try your hand with one, be sure to have a reliable delivery attachment available as a backup. And fully
educate yourself in all aspects of safety (the proper quality batteries to use with your RBA-battery device, ohms/voltage relationship, knowing how to use a multimeter correctly, etc) BEFORE purchasing an RBA.
I've made a resource for those vapors considering their first RBA:
http://www.e-cigarette-forum.com/fo...-tips-vapors-looking-try-their-first-rba.html
I've also made a cartotank setup guide that you might find some helpful tips for your cartotank experience:
http://www.e-cigarette-forum.com/forum/blogs/baditude/3710-5-cartomizer-tank-setup.html