I thought I'd give my opinion on this one as there won't be many out there to argue with me .
Number one, it's one hell of a big heavy lump. It's a big strong lad's gun. Anorexic racing ferrets, forget it. Not aesthetically beautiful, but handsome in a rugged sort of way. Well put together, with a good lump of walnut under it. Mine has pretty plain figuring, but it's nicer than plain beech.
Before you consider one of these, have a few months on a bullworker first. You'll need it to cock the Park. The cocking is achieved by pulling a very short (too short?) cocking lever which acts upon a motorcycle chain to set the twin opposing pistons.
Loading the pellet is a doddle, using a side loading bolt, much like the Theoben rapids. Good safety catch at the rear of the action. Easily thumbed down before taking the shot.
Trigger is a bit iffy. Plenty of work on it can get good results, but it's much stiffer, heavy, and impresice for my taste without a bit of work on it. Once set up to your personal preferences, it holds well.
The actual firing cycle is smooth as silk. Very like the much vaunted Whiscombe, but without the price tag. Little or no recoil. I can place a pellet on the elevetion turret of mine, fire it, and the pellet stays put. That'll do for me.
Accuracy. Mine's a .22, so the accuracy is not as good as a .177. Saying that, it will match a .177 out to 40yds on a nice calm day, from one hole groups out to 30yds and less than 1/2" at 40 yds. After 40yds, it starts to open out a bit: On a calm day it will do sub 1" out to 55yds. Wind affects the .22 much more than the .177.
Major difficulties getting spares.
Bigger difficulties getting someone brave enough, and knowledgable enough to open one up and service it for you. (But these guys are out there).
Mercury S .22. FWB mod 90. Theoben evolution .177. AA S400 in .177. Diana mod 46 stutzen .177. XTX tuned .25 Scorpion in custom stock. HW100KT in rosewood stock .177. Falcon fn19 .20. Walther lgv .177.Aren't I a lucky little boy?