Both. I have a "Great White" tank that I use a home compressor to keep it topped off. When it gets to 35-3600, I run it back up to 4200-4300psi. I don't push my compressor to the full 4500.
I saw the Daystate come up with its digital regulation and programming. I've seen mixed opinions on it. Many shooters prefer a gun that makes regulator and hammer adjustment easy, which is something FX is great for. Other shooters prefer a set-it-and-forget reliable, simple PCP like a RAW and just pay a tuner to take care of that so they can focus on shooting. With a RAW you really don't need to send it out because they are manually tuned from the factory. (At least they were, when Martin ran the show - hopefully that hasn't changed)
I myself do not like shooting bullpups or guns made only of black metal. I like wood. I love the feel of a GRS stock - if they were more durable I'd own everything on a GRS.
Slugs get interesting at longer range and higher power. Definitely excellent for pesting, although for groundhogs I preferred pointed pellets so that they would always punch through their hide. I've tried a wide range of slugs in my high power .22 and .30 and never found one that outperformed the best pellet in good conditions. And yet I still buy and test new slugs, hoping to finally find the perfect slug.
Most firearm shooters don't immediately appreciate the fall-off of airgun projectile energy vs distance. It doesn't limit airguns to 50 yards or anything, but be aware that the 0-50y, 50-100y, and 100y+ accuracy and ballistic regimes are each different worlds. I suggest planning on using your airgun to 50y and depending on your situation, you may find it fun and effective out further than that. (I suggest *not* setting your expectations around 150y accuracy for your first airgun. That very well may not pan out.)
I never shot raccoons, skunks, or opossums. I eliminated whatever what was attracting them and they always moved along. I had a little creek at the front of my property and the one or two times an opossum wandered into the barn I carried it out by the tail across the creek and never saw it again. I did have to shoot at a fox once to keep it away and I killed multiple groundhogs because we kept horses and groundhog holes are a direct threat to horses. I also tried to reduce house sparrows in the barn and starlings generally. Any airgun can take out those little birds.