Not sure what you mean by doing "1 liter a minute" - that really does not relate to speed of fill . . .
The specs on the link for the GX pump work out to a flow rate of about 23 liters a minute, if that helps . . .
But if you want to compare them directly, both links give a fill time for a 6.8L tank from 0-4500 psi. The Tuxing says 21 minutes, and the GX says 90 minutes, so it looks like the Tuxing is about 3 times as fast. Of course the GX is also available with a dualk cylinder model that would drop it to only being about twice as fast.
Honestly, speed of fill is over rated - even 21 minutes is too long if you have to baby sit the compressor as it runs, which from what I heard you pretty much want to do. From what I have heard on the GX those can be left on their own to run, plus they are quiet enough not to disturb the whole house.
I'd take the GX myself . . .
This is my honest opinion of the compressor as a machine, from a guy who services many machines and mills my own parts where i can.
It's whichever fits the user best. I had a gx die and couldn't get the parts I needed and couldn't make soooo it got scrapped into the empire of dirt
. 1 liter per minute(well just shy) along with the ideal gas law can help you calculate fill times.
I use hpa more in my profession than I do for my air rifles lately and have to fill 66 and 88 cubic foot scbas(i dont know the metric) so fill speed and and cast iron was somewhat important for me after burning up 3 hengs, a cx, and my shooting partner's generic orange shoebox that twisted the motor shaft off, I needed something a little more modular and over built.
The price was lower than the cx, till the air freight too which was a bummer, and the power use rating was optimistic at best. The lra on startup and load towards 300 bar draws too much for anything but a new breaker on a dedicated 30 amp circuit in the 120v flavor which I DO NOT recommend getting. I thought my 5.5kva genset could start it, it cannot.
The build quality :
Castings - decent
Plumbing - mediocre, this is the biggest flaw imo, but it didn't and doesn't leak.
Air drying-decent oil water speration stage works well, the filtration stage uses the generic purple filters acrylic cartridge inside with felt pads charcoal and molecular sieves, and thus far has shown little to no condensate in the tanks but I wish it were more industrial grade and had more capacity for sieves.
Electrical - the start and run capacitors are external from the extruded sealed motor housing, the mag switch is in its own case, switch box and breakers are industrial generic Legos like you'd get from McMaster carr for factory automation.
Chassis-the safety shrouds are rattle prone and will be getting some tig welder treatment one day. Buuuuuut, the frame is pre punched for a couple motor options or even a gasoline engine so it can be retrofit. Finish on the frame is nice, paint on the compressor assembly is silver rattle can paint.
If they didn't require the air freight to get it from Ali chinesium express it would be a smoking deal. Mine came setup for 205 bar and the factory sent me a video tutorial on how to adjust parts after I figured out the Bov myself. The auto stop is a weird one that could be dangerous to adjust if the unit is energized and could electrocute youif you just jumped in not knowing. So i used my shoebox and a multimeter to pressurize and adjust mine with no electricity on.
Ive had mine for 2 years now and have some hours on it and I am very pleased. I would not recommend this compressor to most agn users having discovered the general technical prowess over the last couple years. It's fast enough and high hp enough that a mistake could be a really big one really quickly, like losing a finger or electrocution adjusting it, aside from pressure vessel problems. It's on par with power and danger of a table saw or medium sized wood shaper (my profession) and should be treated with the same respect. I've had zero break downs, zero leaks of air or oil as well. You get a full rebuild kit in the box with piston rings and orings as well as reed valves too and mine had a German oil filled gauge in a shipping pic before somebody between customs and delivery stole it.
It fills your typical scba or scuba cylinders faster than a cx4 can fill a 92ci/1l buddy bottle. It took a while to fill the big cylinder in the pic, but the big one holds more than the two biggest "regular" cylinders to the left of it combined, so I treated it like I did my cx4 and fill in 1000 psi Incriments with a cool down period between. Due to labeling the large cylinder allowed me to metric convert, and it has a water capacity of 17.3 liters.
Buy what suits YOUR needs and budget, i hope the info ive left behind is somewhat helpful and useful. I'm a gadget and machinery snob before a brand loyalist and a perpetual tuner/hobby machinist. I've bought plenty of junk and im happy to call it out when I see what it is to save others the trouble.
gxpumpofficial.com 
