If you already have a PCP

I acquired a few guns before I got a compressor. I got a Shoebox early on but I was too impatient and only used it twice. I had a very reliable place that filled my tanks so it was never hard for me to get cheap air. The paintball shop only charged $1.50 per 1000 psi and is only a 10-15 minute drive and they are open 6 days a week. But i wanted to be free to fill my tanks whenever I wanted to so i worked my way up to a full size shop compressor.
 
Absolutely a compressor!

I too tried a ShoeboxF8. Not bad for what I paid for it, but for twice the amount (at the time), you won't need a shop compressor . To me, that was a big plus. Speed is another. If I empty my small tank (from 4500 to 3000, or 7 gun refills), it takes my Omega Air Charger about 15 to 20 minutes or so to refill it, depending on the ambient temperature. The ShoeboxF8 took a little over an hour. 

There is a sidelight to this. If you do own a quick refilling method (no trips to the dive shop etc.), you end up shooting a lot more. And most of the time, a bit less conservative (hurried shots). This can be a good thing in my opinion, if you're trying to improve your offhand shooting ability. 
 
To justify a compressor there really needs to be the need for air and the availability to shoot. If it is difficult to find a place to shoot or limited available time, it might be more economical to find a fill station. We as shooter see the need for the compressor, and I got tired of going to the paintball range every weekend to get my tank filled. It was only open on the weekends so it also ate into my shooting time. I think the compressor comes later once you have "swollowed the hook" and KNOW you want to continue to shoot PCP's. During the summer months, I shoot nearly every day, so it makes sense to get a compressor. But If I was limited to "shooting at a range" on the weekends, not sure it make sense unless you have an hour drive to get your tank filled. So, yes i would get a compressor if you want to stay in the PCP hobby, but you might want to make sure by purchasing that nice rifle and tank set-up first. Once you tire of going to the fill center, then you get the compressor.

Unless you have easy access to air, you probably won't stay in the hobby. This was a good post, Norman!
 
This year for me, compressor!
Just moved and think the closest year round air is a few hundred miles away, got eh altros booster. As I don't have $2,000 to spend on anything but do still own some pre-charged rigs and love to shoot and I have nothing but time on my hands, so it is prefect for my current situation.
When I lived in Fla. I had a scuba shop 1/2 mile S. & closer to the North and fills were $3.00 for anything , used 110cf Steel 3,450psi tanks for $50.00 - got 2 - never would have gotten a compressor but WOULD have gotten a large CF.
I also look at it like the airguns though, buy the best you can and if I could have gotten a Bauer I would have evn if it's a bit much for just me.

John