I have a Sandridge TF5, no need for upgrades.
68cu" 3000 psi Flatline.
Strengths:
For the money, this is absolutley the best compressed system around. The on/off is the simplest thing to operate (even a brain-dead lab chimp could figure it out). The unit comes with a drop forward and micro-gauges. Fully adjustable... where else are you going to get all this for the price (the above stated MSRP of $229 is not accurate, however). AGD's cutomer service is tremendous. Plus, it's relatively small if you compare it to your average screw-in type tank with all the needed hardware.
Weaknesses:
Nothing fits except the stock drop-forward, which is moderate and not forward enough for front players. I'd like to see something adjustable come with this. Also, you need to grow about 3 extra (abnormally strong) fingers to remove and install the drop-forward. These are minor gripes relative to how much I like this system.
Conclusion:
It's not perfect so I can't give it a 10. I'd like to give it a 9.3 but I'll have to round down. Bottomline (no pun intended): this IS the best system for the money. Pound for pound champion of compressed systems...