A search here on TSB will get you more detailed information, but here are a few general differences between the two ink systems.
Straight waterbase or dc? Obviously it isn't as easy to print regular waterbase colors on dark shirts and get a good bright print. While there are wb inks and bases for printing on darks it isn't going to give you the type of coverage and bright colors that you could get with plastisol. So while straight waterbase on darks is possible it isn't nearly as straightforward as plastisol.
Even DC waterbase inks, though they are pretty bright printed on darks, really can't match a bullet proof plastisol ink layer for brightness and opacity (though I won't wear a thick deposit plastisol shirt). The advantage to DC is in the hand (really nice), no need for flashing, the reduced issues with fibrillation (a killer problem over time on my light hand plastisol prints) and no unsightly cracking like you get on older washed thick deposit plastisol prints.
DC inks have the drawback of limited life span when activated and the waste of left over ink, being hard to see pinholes and the like until they actually discharge and not being able to blow out the resulting spot. They require different emulsions, block out, maybe a better scale (for PC systems) and most DC systems are rather smelly. Shirts printed with most DC ink systems should either be washed or tagged wash before wearing, particularly if they are sold at retail. There are ink systems like Magna that don't smell as much during the print process and don't require washing or tagging. It all depends on your end user market.
Gas dryers are preferred, but electric dryers with some forced air flow will work just fine. Radiant only dryers can work, but you better have your cure dialed in! You can expect that your dryers throughput capability will be reduced because of the longer dwell time required for wb and DC inks compared to plastisol . That can be big if you are running an automatic or cranking out one or two color prints on a manual.
Reading old posts will give you a lot more info regarding actual printing techniques and the merits of different inks/equipment. I really think the choice between plastisol and wb depends on your end user. I probably would stick to a heavy deposit plastisol print for my local construction company unless they were sophisticated enough to ask for a light hand print. I wouldn't even think of retailing higher end garments that were printed with bullet proof plastisol.
One last comment. I hated printing hoodies with plastisol. Getting good coverage without having as many issues with spread, lifting of the material or anything like that due to the stickiness or thickness of the plastisol (on darks) makes WB DC my new favorite.
There is no one solution for everything under the sun. Shoot for what will work in your market.
