CAP Ebb & grow bucket system suck. Just as much as CAP does as a company. Yes they have "upgraded" those buckets 3 times soo far, but they are too ignorant to figure out what is wrong. I do not know about coco in those buckets. Even with hydroton that system is the nesting ground for Gnats. Root problems are normal with CAP E&G beacouse of poor design coused by ignorant people designing grow. equipment.
Anyway....I would say go with the hydroton, also I'll give you "short" list of the things that you should modify in the order to get that "bucket" system to work.
1.repipe system with 1", or at least 3/4" pipe(hose)
2.change to a bigger pumps.
3.upgrade the buckets to 3 1/2 or 5 gal buckets with covers with 8" mesh baskets.
4.instal large volume air pump and run air stone or a diffuser into every bucket.
5.take 1" pvc pipe and cut it into 1" pieces. Use those as a spacers(put those in between inner and outer buckets) so your roots do not seat in that nasty stagnate stinky watter. I would like to get a chance to feed one of those fat asses from CAP with that nastiness to see how would they like it, becouse my plants didn't.
6.do NOT put any "bennies" in you tank (reservoir), acctualy do not put anything in the powder form in your tank. It will eventually clog the lines.
7.do NOT use anything that will foam up your tank 'couse it will couse overflow sensor to stick, and you'll find yourself picking up your nutes off the floor 2-3 times a week.
8.Do NOT even think about going organic, Ebb& Grow in not even able to finnish a run with salts in it's original configuration.
There is more to it.
Use caution any time you dealing with CAP, seems that they have a lots of quality control problems lately. I went thruu 3 CO2 generators from CAP, got 'em new at the store, none of them worked out of the box. Their controler XCg-1 or whatever its called, stoped working on me after 4 weeks.
No problems after I have changed everything to "Sentinel". They also have a new "bucket" system. It seems that "sentinel" actually have some idea about what is needed in the order for plant to "survive". Haven't seen it but by the spec. it seems that sentinel system is drasticaly improved when compared to CAP.