For a long traditional looking gun I think an Avenge X is a good option. I have an original Avenger with the cheap feeling plastic stock and I like it except it is hugely long which I don't like. It is far easier to tune than my favorite guns since the regulator is external. It has plastic where I think they should have used aluminum, however, and I think that got fixed in the Avenge X. I shoot from my left shoulder, however, so the bullpup with it's rear cocking does not work at all for me. And I prefer short guns.
My favorite PCP is my 3 P35s. I have a 177, a 22, and a 25. They have a whole lot more metal and a whole lot less plastic in the action than my Avenger. There is a range of accuracy in my P35s with the best one being better than the Avenger and the worst one being significantly worse. I've taken the most squirrels with the least accurate one, however, I got it first. Adjusting the regulator requires degassing and dissassembly of the air tube. It is not terribly hard but it takes a lot more time than turning a screw on the Avenger. There is also no gauge on the regulated chamber. I can tell my regulator setting by watching velocity as the tank pressure decreases. When velocity changes you've found where the regulator is. The big disadvantage of the P35s is the scope is over 2.5 inches above the barrel. So the POI will be 2.5+ inches low at the end of the barrel and will not get up close to the line of sight until over 20 yards from the muzzle. This is a pain in the backside on close shots. A conventional rifle, like the Avenger will have the scope at least an inch closer to the bore and the amount they hit low is at least an inch less and goes away faster. I think a P35 is best in a 22. It takes some work to get one to shoot heavy 25 grain projectiles a reasonable speed. The Stoeger bullshark is almost exactly the same gun. It has a 40mm longer barrel and a different stock. You have to order the P35 from Krale but Stoegers are available in the U. S. These guns cock in the middle and have flush magazines. If you get one you'll probably have to fix it yourself but mine have only needed the occasional O-ring which I think all PCP users should learn to do. They have a warranty but I don't know of any service center for them. But I haven't needed one. P35s come with extra O-rings and the only special tool you should need. You'll need some metric allen wrenches.
The GS CX4 seems like a reasonable option. I like my Yong Heng + SCBA tank, however. I fill the tank from the compressor and the guns from the tank. Tank filling is very quiet and fast. A 350W compressor is going to take awhile to fill a gun and a really long time to fill a tank. A Yong Heng pulls about 1500W and is thus quite a bit faster. It is also very noisy and needs a bucket of cooling water. If you have a place you can set it up and leave it set up like I do it works well. If I need to refill away from home I just take the SCBA tank. It will give me about 10 refills which is normally plenty. My SCBA tank is an expired one I bought off ebay for about $100. Works well. I don't believe there is a scientific basis for the DOT 15 year lifetime on SCBA tanks. I also would rather trust an old Scott tank in good condition than a new tank from China (but my guns and compressor were made in China).