You can improve on the HF blaster (and many others) by converting it to a bottom-feed "venturi" arrangement as opposed to the siphon type pickup tube:
If you have enough compressor, converting to one of these type guns, and running 1/2" hoses throughout, will get you some really awesome performance, as well:
Mike at Tacoma Company is a great guy, extremely knowledgeable and his stuff is priced very reasonably. He sells a kit specifically for upgrading the HF cabinets, because so many folks are in the same situation.
In my case, I was building my own blast cabinet and knew that I wanted to use this type of venturi arrangement. The last one I built when I lived in NY, circa 1988, used a siphon tube.
I also got my gloves, glove flanges, and gun from Mike.
I am using an abrasive blend of 50/50 crushed glass and garnet and find it works very well for typical paint prep/light rust removal. Mike mentioned that blasting pressures should be kept to between 50-60 PSI, higher than that just accelerates the breakdown of the media without much change in productivity.
Here is the cabinet I made, it is 30x30x48. The stand is 2" aluminum welded square tubing. Four 100W equivalent CFLs are in a box over the top located over an additional window.
Rather than use a foot pedal air valve, I used a 110V 1/2" NPT solenoid valve (5/8" internal ports) and a foot switch pedal.
Use clear film as Greg mentioned, to protect your viewing pane. I bought my film from Grainger, it is made for blast cabinets, is crystal clear, and is WAY cheaper than the stuff TIP sells (might be the same stuff).