You are likely getting the burnt taste because your cart filler is not wicking
juice to the bridge well enough. Burnt generally means dry atty. Unfortunately if you are using the original filler material (fluval) in the cart, this is notorious for doing just that, and so people have spent considerable time finding new filler materials. Of all of them, I would say the aquarium filter foam is the best (Marineland makes the "Blue Foam"). You could also go to a tank style system which holds the
juice in a tank and delivers it quite well and quite consistently to the bridge through a small hole.
To make sure this is the problem, try dripping 4 drops of juice directly on the bridge and putting an empty cart on, and vape. If the burnt taste is gone for several puffs, it was a wicking problem with the cart. Before you try an LR atty, which will vape even hotter than a regular one, I would try to solve the cart issue.
As for cartos, I am a big fan of either 3.0 or 2.4 ohm Boge soft tips. I'm using a 2.4 ohm carto on an eGo right now. Litecig.com has them, as well as many other vendors:
510 LOW RESISTANCE BOGE SOFT CAP Blank Cartomizers
These are LR 2 ohm according to the site, but I have found that most claims of resistance are a bit lower than the actual measured resistance. Mine are about 2.4 ohms, still lower than the regular ones:
510 Blank Cartomizers
Soft tip allows easy opening to add more juice. I like using them with a drip tip and I just drip in to top them off throughout the day. They can be refilled many times, and they clean up well with alcohol. Nice draw, better flavor from juices than other types I've tried. I think it is the filler material they use, which is courser than the older, albeit slightly cheaper, models. Great low maintenance vaping for all day. Expect around $8 for 5, although you can sometimes find sales for as low as $5 for 5. I get several weeks out of mine, if not more. If the site does not say "soft tip" it may be the hard tip kind. Also good, but I generally end up using a tool to break out the hard tip and glue so I can drip-tip it. Both types hold about 1 mL of liquid, give or take.
You might also consider CE2 type cartos. They come in metal tube and clear tube styles. Very different technology than regular cartos. I would recommend getting Boge soft tips first, learn the ins and outs of them, then perhaps look into the more advanced type cartos.
