These are absolutely functional and I used this type of compressor for a while (although my Yong Heng kept having issues).
One reason to get a slightly better compressor is because of the racket and the hassle as far as setting one of these things up and the amount of space it occupies. The vevor is so loud it has to be in the basement or garage and definitely requires ear protection, and it takes up a fair amount of space with the bucket and hoses, and both the compressor and the water pump need to be plugged in.
I got a gx cs4 when there was a sale after considering gx compressors for about a year - it is a better experience by a fair margin and i don't regret the purchase.
Has a built in water tank so it takes up very little space, I don't need to wear ear protection and can have a conversation while it's running in the room. It is a much slower cycle - more like a pumping sound and no vibration. No need to run it in the basement or garage which I appreciate. Also since this pump has a much higher fill rating, it is not being pushed to its upper limit when it tops off my 4500 psi buddy bottle.
The fact that it doesn't scare off my old cat, and that it's portable and can be powered by 12 v DC / automobile is icing on the cake.