Genetics is the biggest factor in flowering time and resin production. Remember the resin amount has nothing to do with the high. For example Afghani strains typically have been bred to produce hashish. So the plants tend to produce a lot of trichomes. They have a short growing season in the Hindu Kush mountains so they need strains that will finish before the rain/snow starts. That's why Afghani plants finish so fast. I've seen pure Afghani strains finish in under 8 weeks. The high is usually more of a body stone. Think couch-lock.
Equatorial Sativas tend to produce a small amount of trichomes and the crystals are usually smaller in size. I'm sure you've all smoked weed that after a few hits doesn't make you any higher. You may stay higher longer but once you hit the ceiling that's it. A good sativa will have a very high ceiling which means the more you smoke, the higher you get. The high can be mind-blowing! Almost like a mild acid or shrooms.
Pure Sativas take forever to finish! I once grew some Colombian Gold just for old times sake and the fucking thing was still putting out white hairs at 14 weeks! Sativas have poor bag appeal compared to the big name Kush strains. They are kind of leafy and the buds aren't usually as dense. Think light, airy, yellow/green buds. Small calyxes without a lot of resin. You old school smokers may remember the Thai-Sticks from the 70's. It didn't look anything like what we smoke today. What may look like skank is actually dank.
Okay why hydro? These guys nailed most of the reasons. It's easy to read a number and figure out if it's too high or low. I learned numbers like in 6th grade or something so I like the shit outta hydro! Still what you grow in is just one part of the equation. Light is what powers photosynthesis. Plants can handle an enormous amount of light. It's really only the heat that you have to worry about. You really won't see massive growth rates if you have small lights. If you want to know what size lights to get think dick size. If you could choose your dick size what would you pick? This also applies to the ladies in the audience...and please don't give me any of that motion in the ocean crap!
People make a big deal about nutrients. Fuck that, it's easy to give the plant nutes. In fact you can burn the fuck out your plants pretty easily if you don't know your numbers. Water is not much of an issue either. CO2 is a fairly big deal because the plants are fed with carbon based sugars. The plant gets it's CO2 through it's leaves. The only way to increase CO2 is by bottle or burner. It's good for another 20%-30% for soil and hydro.
Oh yea, hydro... So the big deal with hydro is Oxygen. Everyone knows that plants give off oxygen but no one really thinks much about the fact that the plants also use it. What's interesting is that plants get their oxygen through their root system in a gaseous form. Basically that means the plant's roots need O2 and the more you can give them, the better! The problem is when you give them so much the roots dry out. That's where the timer comes in. Every method I know of has some sort of a watering schedule whether it's drain to waste or Aeroponics. It all has a dry period to allow maximum oxygen to the roots. So hydroponics is not actually about the water it's about the air... strange but true...
Oh yea, if you give plants a shit load of light, just the right amount of nutes, water timed like an athlete, You'll can get freak of nature growth rates. You can almost watch them grow. I shit you not. Here is a photo so you can see what I'm talking about. Hydro - Hell Yes...Aero - Fuck Yea! It's that simple.