I have 2 friends who have tried this with the inception coming mainly from the hydro store employees. The problem lies in the T5's penetration..... past 12 inches they are rendered "inefficient" and well the initial stretch of 12/12 can often reach beyond that.. so even with no veg time.... ideally your still lollipoping in flowering...it really will also depend greatly on genetics...but the Bud I saw were dense and stinky..... no quality lost just per watt not as efficient. 430 something watts i believe they are and I have yet to see either of them yield over 5 ounces from the 6 plants they get under there. they are twins too who do everything the same as each other even tattos... weird lol
Pros-
cheap and easy to set up/run
requires minimal cooling power
nice colas due to close light to bud proximity
Cons
Low intensity, low penetration
the wattage is spread across the entire length and quantity of the bulbs
airy lower buds
Overall can do well with red spectrum bulbs but not as efficient. The way indoors is even with HiD lights its hard to penetrate enough to veg a plant past a week or three without using side lighting. HiD also have the advantage of sending out all of the wattage and light from one central point. Imitating the sun closest in terms of all indoor lighting. Some have their own take though. That's just my 2 pennies.