A department store nearby recently replaced all of the halogen PARs in their track heads (easily over 100 bulbs) with these bulbs. Nice light output. I was checking around and these things are about $60 a bulb! Does anyone have one of these and what do you think of it? I would like one but that's a bit too expensive.

I've seen some pictures. What i would like to know, what kind of ballast is there, if DC, LFAC or HFAC...

I don't know about the Philips, but I received a Sylvania version of this lamp as a sample earlier this year.  I'll have to dig it out and see how the ballast on that one is constructed.

So they typically have an electronic ballast built into the bulb? I was thinking more along the lines of a tungsten filament as a ballast... like the self-ballasted mercury vapors I have.

Yes,the Sylvania version has an integrated electronic ballast - similar to that of a CFL.  I'm not sure how well such a ballast would handle the heat, however.  Only time will tell!

I believe it would have to be an electronic ballast as it is MH. So far I haven't seen a higher wattage than 25.

Indeed it is electronic, for 20W lamps the thermal stress would be even lower then 20W CFL, as CMH gives majority of it's "waste heat" as IR radiation, so it goes away with the light and does not heat the lamp's surrounding.
But "electronic ballasts" is very generic term. It always start with a rectifier, but then concepts differ:
It might supply the lamp with high frequency AC - the electronic create a high frequency AC voltage supply and the lamp is then ballasted by serial reactor, what is very small due to high frequency involved (exactly like CFL). It is the simplest and usually most efficient style. But in the literature about HID this type of ballast is not favorized, as it poses a risk of acoustic standing waves , so uneven heat distribution in the burner.
Second simplest is the DC - the electronic form a DCDC controlled in the way it form a "constant current" (current into the load does not depend on the load voltage drop) or for HID's often "constant power". This would require special burner design for DC operation, what is not out of reach for these lampmakers, but prevent them from sharing "standard" burners with other lamp styles.
The most complex is the Low Frequency AC, what is the "DC" with a device, that swap polarity of the lamp current with the low frequency. This form are using nearly all high quality HID ballasts, but it is the most complex and so expensive form, what in my impression would be prohibitive for the disposable form (integrated into the lamp assembly)

Is there any reason the ballast couldn't just be a tungsten filament?

Is there any reason the ballast couldn't just be a tungsten filament?

Efficiency of such ballast - it would be only about 50%, what would mean barely 45..50lm/W of otherwise 90lm/W CMH capsule (5lm/W would come from the filament ballast).

Tungsten ballasted were these products , achieving 41lm/W. They used quartz HV (pulse) start DC operated MH capsules ballasted by tungsten filament. They operate at DC, as the diode rectifier bridge allow to decouple the low OCV power ballast from higher voltage (from doubler circuity) arc-keeper (to avoid arc extinguish during mains zero-cross). Such trick allow to use higher arc voltage, so lower ballast drop, so losses, as no post-zero-cross-restrike is necessary, when the arc is not allowed to exinguish (as in normal, e.g. magnetic ballast, circuity).

I just found a new-in-the-box Philips MASTERColor 25W MH spot with integrated ballast at a salvage place.  The price on it was $7.10 + everything in the store was 25 percent off that day.  I know this was a mistake in the price. 

These are very nice lamps.  When first turned on, the light is very dim but white, almost like an LED.  Within a minute or two, it grows in intensity, first becoming a bluish-green and then the familiar pinkish white with excellent color rendering.  The 10 degree spot has near perfect optics -- the beam is very tight and clean.  You would never be able to achieve this level of performance with a CFL.

The bulb stays very cool.  I ran the bulb in my lap for about ten minutes and only the glass face got a little warm.  The plastic rear of the bulb stayed cool.  I guess MH bulbs put out very little IR energy.

The bulb gives off a slight hum while in operation.

The bulb has a warning that says it can only be used in dry locations. I would like to use it outside in a PAR fixture but it would have to be one with a shield that protects the bulb.

I would have preferred to have the flood version of this bulb to use in a torchiere floor lamp but this was the only sample of this bulb at the store.

I predict that these bulbs will become very common and are a great replacement for halogen PARs wherever dimming is not required.  Hopefully, the price will come down (probably not to the $5 or so that I paid!).

Hope everyone had an awesome Thanksgiving.