I can speak to the Marauder. Excellent platform. I've had one for over 5 years and love it as an entry level gun. Kral's get excellent reviews, but if you are looking at the bullpup versions (and this holds true for all bullpups with rear cocking), I really don't like the rear cocking. Personal preference there.
I would avoid the Gauntlet. Too many stories about how it's got great potential, but needs a LOT OF WORK to get there. You might get lucky, but for a first PCP, get one with a good track record. Known for crappy trigger out of the box, really rough bolt, etc. Trigger can be adjusted, bolt polished, but who wants a project gun new out of the box?
If you can spring for an FX, the Streamline is a fantastic gun. I'd avoid the newer Dreamline for a year or so, until FX works the bugs out. Just standard for me, I'm a late adopter. The Streamline is a proven platform.
Back to the Marauder - it's got a couple things no one else at that price point has, and lacks one thing.
The Marauder is adjustable, so if you want to shoot Crosman 14.3 grain pellets at 900fps, you can adjust the gun to make that happen. If you want to shoot a .22 with the 25 grain JSB's so it has the hitting power of a .25 caliber, you can adjust the gun to do that. If you want to shoot the 18.3 grain JSB's at 830fps, you can do that. As you gain experience, you may want to add a regulator, and those are available after market. I just put one in that cost $69 from Lithuania and it works fantastically so far.
It does lack a regulator, but I haven't found that to be a problem. I got 30 shots without a regulator with a small enough differential that it was acceptable. I added the regulator just to see what it could do. Still have tuning to do with the reg, to make the gun as efficient as possible.
The Marauder also has a nice adjustable trigger. It's adjusted well out of the box, so no adjustments needed, but the adjustments are there if you want a lighter trigger. Quiet, sort of sets the standard for back yard friendly. Rotary magazine that's the foundation design for most rotaries out there. The new barrels from Crosman are extremely accurate. Mine is 5 years old, stock barrel, and gets 1.5 inch groups at 75 yards, so for the price, it's accurate.
My main complaints are that it is a long gun at 42 inches, and when you cock the gun, the bolt is compressing a 10 pound spring, so the bolt pull is stiff, but it is smooth. Maintenance is a snap. I just replaced all the O-Rings and it took about 20 minutes. Just a few rings make the whole gun go. The Marauder is a nice simple design.
Parts - If you need parts, at least my experience with Crossman is that I called, ordered, and they shipped within a day or so. Where you are not in the US, do check for suppliers. Never know when you'll need a part. I have several Crosman guns, along with an FX Impact. Either company really backs their products.
From your profile, looks like you are in South Africa, so do check local laws. From watching Matt Dubber, it seems a .22 won't be a problem, but do check as I am in the US with completely different rules and regulations.
Good luck on your purchase. Except for the Gauntlet, I don't think there's a bad choice on the list. The Gauntlet is an excellent design, but poor execution at this point. (just my opinion)
