What is the best 600w ballest and bulb?

Time to upgrade and wanna hear what you guys think before I invest in some new gear.

Just started using these. They seem like a solidly built light,haven't been running them but a couple of months,but no problems. Seem a lot brighter than others I have used.
best price I have found: http://www.plantlightinghydroponics.com/digilux-super-hps-bulbs-c-374_837.html Using them in my new Galaxy Selecta watt 1000w ballast