The penstyle attys are awesome. I only use low bridge now (302 from Joye is a terrific atomizer). There are several low bridge out there. Ask about the air holes. BE112, RN4072 and the 302 are great. Boge has a 4 hole and Joye is a 2 hole (large holes).
If you go with the 302, DO pick up the cartridges for them. The length is different than the 801 and makes a big difference when using them (plus they're the hard tip, which I prefer anyway as the 801 rubber tips have a nasty taste).
Chad at Ecigsupply for all your e-cig needs carries the 302 and has good prices.
If you want to use filling in carts on those, the AquaClear foam from PetCo is the best. I won't use anything else now.
I tried some of the 510 mega cart/atty. Not much difference to me. I won't waste the extra money on them again.
I prefer the hard-tip 302 carts myself - they fit my 801 atties perfectly and don't have the rubbery taste.