Advantages of M80 (HQI) over M138 (Pulse)?

[apepper]

Is the main advantage of the M80 (HQI) ballast over the M138 (pulse start) ballast, the higher PAR output you get with the M80? Based on the tests done by Joe Burger (http://www.cnidarianreef.com) the current draw for the M80 is higher than with the standard PFO ballast (is this a pulse start ballast), hence the higher output I assume. So if I don't need the extra PAR (I have a small tank...I know I know) then should I just stick with the M138 with lower power consumption and lower initial cost?

Are there any other advantages of the HQI ballast over a pulse start ballast for standard SE 250W bulbs (eg. Sun10K), such as longevity, reliability? Does the higher output introduce a color shift?

Alex