Sand blasting

Thanks for the replies. 
I'm looking at a a few but 2 stand out.
1 has 100ltr tank and 13.6 cfm the other is has a smaller 50ltr tank but it does 16.9 cfm.
Choices, Choices 

I would go for the unit with the greater CFM throughput. Although you would only require that volume when you were using air hungry devices (media blasting, needle scaler etc), for normal applications the throughput capacity would replenish the smaller receiver vessels rapidly.
What wattage does your favourite unit consume? A twin cylinder unit at two k’watt should keep you on top of the job. The next step is three phase or internal combustion.
M

As AP says the CFM is the more important figure for media blasting, I used two 13CFM compressors when blasting the GT and even then I would run out of air. I was using a 5mm nozzle though, I gave the 4mm version to a friend who then lost it, that would have been a perfect balance. I had finished blasting the GT before a replacement 4mm nozzle had left China.