OK, heres the deal on dig ballasts.
Pros: Much lighter (weigh less) & burn MUCH cooler. They are a little more efficient. They do draw slightly less power and produce slightly more lumens compared to magnetics. Some of the newer ones offer a "dimmer" option (which is not particularly useful IMO). When you dim the ballast IT DOES NOT DRAW LESS POWER. Running a 1000w dimmable ballast on the 500w setting STILL DRAWS 1000 WATTS.
Cons: MUCH more expensive. They do cause RF (radio frequency) interference in some cases. Using multiple (10+) ballasts have caused peoples power meters & climate controllers to act up. If you use the "superlumens" switch on Lumateks they burn out your bulbs insanely fast. Not all digital ballasts are generator ready (do your homework). NextGen's are not UL listed (if i'm not mistaken) so if they cause a fire your insurance WILL NOT COVER IT.
Being said, I have extensive knowledge of all major brands of digital ballasts on the market today. Quantum, Lumatek, GGL, Galaxy, NextGen, Phantom, BadAss, & a few others. I would say HANDS DOWN Quantums are the absolute best ballast on the market. They offer a 3 yr+2yr prorated warranty. They come with both 120v & 240v cords & are dimmable. Phantoms are also very nice ballasts, rigorously tested & HIGH quality. BadAss is made by Advanced Nutrients and offers some rediculous like 10 or 20 yr warranty but I would advise to wait because they are BRAND new. GGL's are solid but are known to melt where the lampcord plugs into the ballast. Galaxy is good, have never heard of any problems with them. NextGen is OK but overpriced and not UL listed. Lumatek is probably the most popular and also the oldest but NOTORIOUS for problems & blows up Hortilux bulbs regularly. Hortilux just released their new "e-ballast compatible" bulbs so we'll see. I've heard mixed reviews on teh Digilux bulbs. Some guys swear by them and some people say they are totally BS. I know for a FACT they are not putting out anywhere near the lumens they are claiming. I've read the studies and have to say I am less than impressed. Go with Hortilux if you got the money and UltraSun or Plantmax if you don't.
I got my quantums for $150 (600w) & $250 (1000w). PM me for the info.
Also, if you want to see if your ballasts are sending off RFI do the following. Take a radio and turn it on AM. Find a clear station and walk slowly towards your ballast. If/When you hear any distortion/interference/crackling you know you've got a problem.
I've heard that Lumatek had an RF problem at first, but solved it years ago before their purple colored ballasts were even released. The 600W Lumatek has the Hortilux bulb problem. All the other sizes work great with them. This I know personally about the 400W working with the Hortilux bulb.
Question: How do you KNOW the Digilux's do not put out anywhere near the lumens they say? I would like to know because I currently have one, and am thinking about a backup bulb. It seems plenty brighter than my 400, but what do my eyes know?
You almost sound like a commercial and then say to PM for where to buy a Quantum. Thanks if you're helping, but my flag went up a little on that one. No disrespect intended. We don't really know each other after all.
Anyway, I hope my Lumatek 400 and 600 aren't as bad as you say for obvious reasons, I have them. My 400 has been flawless for months, not one hiccup, so I either got a good one, or it's waiting to do something evil any day now.
Also, if you google Lumatek, you get a few posts like yours, almost verbatim. but not very many, and they mostly go back a while. You get more posts recommending a Lumatek.
Kind of weird they have all these problems, yet no one is really complaining. They must be selling quite a few of these because they are at respected stores and internet sites.
I don't have a lot of first hand information about Lumatek, and am not claiming to. I have used the 400 without flaw for months, and a 600 that appears to be operating within normal parameters.
P.S. I don't see Digital being more expensive either. Maybe we're shopping at different locations though.