Yes, had both. You are correct the LGR is easier to scope unless you put a long tubed high variable scope. then the objective bell and length can be problematic. The LGR's Tap breech seals are easy enough to find for replacement. I don't think Pilkington's has any more parts for them. Buck still will work on them though his hands are tied by parts availability. When I had the basic LGR I got pretty good service out of Crosman 10.5's in the back yard shooting Palma style long range. THe LGR universal and running target are highly prized. Be warry of the guy's selling on the old Brad's American air gunner page and certainly about that Corel guy. The LGR trigger is of course fantastic, but people try to reduce it even further. (Don't) its fantastic as it came from factory for the reg. pull for int. comps at the time. The univ / match cheek rest spacers are impossible to find anymore. Do not double short stroke the LGR to get a tad bit more fps. You'll end up breaking the cocking mech inside. Methodically easy and appropriate cocking motions only. They will still shoot .08 c-t-c groups at 10meters all day long plenty good for us old guys wanting a fine machine to recreate with. What's hard is the acrylic front sight inserts. Originals (NO WAY NOT AROUND). Replacements out of Perspex's from England were available at one time. A fully useable and legendary rifle to recreate with even today. Once in a while you'll run across third party made compression seals and parts. PICK THEM UP, no matter.
The FWB 601. Runs around 615 to 560 fps marks depending on pellet weight. Parts are available though you probably will never need them. THE 601 and 603 are legendary and highly prized. Not only for accuracy but strength and service. Hardly ever break unless you're a ham-fisted troglodyte man handling them. You will need the highly scarce "Short" or cut-down loading gate and BKL mounts to scope. It will put the optics very high above action so cheek position can be problematic for short necks. Seals are readily available from Europe. the associated trigger lock works and everything else almost never breaks when operated responsibly. The accuracy potential over the LGR can only be achieved / produced by world class young shooters. BOTH will be just perfect for anyone else on the mortal world. Both are capable of headshots on grasshopper's way past 25 yards in wind. (THIS WILL MAKE YOU FEEL LIKE THE KING OF THE WORLD). Many, many more accessories available for the FWB 601. Value / demand goes easily to the FWB. (Side note) FWB started because of a fall-out by design engineers at Anschutz. They said see ya were going on our own and make better rifles. And they did.
Sum-up: FWD for value / accuracy / available parts - accessories. Walther LGR for the History / ancestry of air guns / Uniqueness. Watch out for the euro sellers on American air gun classifieds.