Airborne,
The RWS Diana 48 was my first serious air gun purchase, and it is still the king of my collection. I don't use it much for pest control because it's over-kill (excuse the pun) for the little rodents I'm after, but it's nice knowing I could take out larger critters with it. Shooting at longer ranges (40-50 yds) is fun. I make a 6" dia. 3/16" stainless disc ring for mercy when I find the center. Ping!
It's a fine piece of German manufacturing, but rather heavy as mentioned. The construction is very robust, and the side lever, while affording fixed barrel accuracy, makes the gun feel a bit fat, too. The rear sight is easy to adjust, and the stock trigger suits me fine.
I won't go into the whole scope thing you're welcome, JoeWayne. And as Joe mentioned, it might not be the gun you want to stroll around in the woods with.
I highly recommend going with the .22 cal, and try using pellets that are on the heavy side. They seem to counter the recoil and smooth out the firing cycle. The .22 cal makes better use of this fine springer's power in my opinion.