t5 vs mh

ive used and still use a 400wmh for veg. recently bought a hydrofarm 4 foot 4 bulb t5 setup. it puts out 20000 lumens im using it to veg some seedlings. it really seems brighter than the mh and the seedlings love it . is it all about lumens or is it the type of light.?

lumens are a measure of light relating to the human eye and have nothing to do with plant growth.

T5s are great. I've read that the 4 ft 6 and 8 bulb is comparable to a 400 watt HID or better because the light is spread out over the 4ft bulbs and not emminating from a single 1" x 8" inch bulb.
Built in ballast, easy to change from 6500 to 2700K or mix.

I think Victor Viscious on here has a great grow going on with them.