Need advise on power module or matrixx ii

[MarsKuo]

Hi, all

I'm survey the T5 lamps on my 500L SPS tanks, there are two consideration so far.
1) Giesemann matrixx ii 8x39W
2) ATI power module. 10x39W

There is no any experience sharing of matrixx ii can be found, although add fans is interesting for me. another concern which is the ballast inside the power module was changed to HEP from Philips or OSRAM, how about the efficiency or performance comparison?

anyone can share your experience of PM with HEP ballast or comments to me.

Thanks.
Mars