I use a combination of both. Basically, I use Seachem's dry stuff for basic chemistry and Kent for more "exotic suplements" and some food. I prefer Seachem's dry to Kent's dry because I get better results, especially with the buffer and calcium. I have used Kent Tech CB before and had decent results. But I never got better than when I moved to dripping Kalkwasser (use any brand you like or pickling lime from the store, they're all the same).
Currently I drip Kalk, bump Ca with Seachem calcium supplement if needed, buffer once a week, almost never touch the Alk supplement with Kalk dosing, dose Mg twice a week (need to with Kalk), and once a week for all the rest except trace and phyto. Trace goes every-other (mainly as an insurance policy probably not necessary, but I have the stuff) and phyto goes in 3x a week.
Breakdown:
Seachem:
Buffer, Calcium (Reef Advantage), Alkalinity Supplement (Reef Builder), Magnesium (going to switch to Epsom salts for that for $$$ savings), Stronium
Kent:
Iodine, Coral Vite (vitamins), Trace elements, Phytoplex (for the clams).