Lumatek IS made in China.
If you want to go digital, go with a high end reputable brand, like Solis Tek. They will stand by your device even if your local dealer goes out of business, like many have around here recently. That said, you will still want to keep a spare ballast around because these are not repairable; they need to go back to the factory for replacement.
A magnetic ballast can be fixed by anyone with a modicum of electrical knowlege with inexpensive, widely available parts. Usually the same day. How long do you want your girls to be left in the dark?
As has been discussed elsewhere on this forum, running your bulbs on a dimmed setting accelerates the aging process; mildly so in the case of HPS, much more seriously for MH. In fact, don't ever run MH at any wattage other than the one printed on the bulb if you want it to last. Not only does the dimming hurt the bulbs, but your PAR output per watt efficiency goes down the tubes, too; for example, at '60%' setting, you're only getting 40-45% of the rated light output.