Matty,
The PST is a great little scope!
I say that even though mine is currently away at the factory getting the "rust problem" fixed.
By all means have a look through one first if you can, and have a read here:
http://www.iceinspace.com.au/index.p...41,320,0,0,1,0
At the bottom of the review I did a little sheet of calculations relating to the PST if you are concerned about resolution.
In terms of bang for your buck, the PST can't be beat!
Al.