Greg,
I have fun any time I am shooting, so it is a little hard to say which Shrew I like best for fun shooting. If you mean just messing around in the back yard without getting fatigued, I would say that my lighter poundage Shrews are the best. Since my lightest is a 43#@28" Lil Favorite, then that bow with fairly light arrows would be the one. My favorite Shrew would be a Classic Hunter with foam cores (and maybe carbon backing) and Bow Bolt. My normal hunting weights run about 52 to 57 pounds at my 29 1/2" draw and fling an arrow very well. At those draw weights I start to feel significant fatigue at about 100 arrows unless I take a break occasionally.
I often shoot up to 300 arrows in a session and quit when my form breaks down. I know I should quit sooner and shoot slower, but every time I try to stop, I think "Just a few more." I can actually shoot my hunting weight bows better at first because I get a cleaner release, but when fatigue sets in my shooting starts getting sloppy unless I drop down in draw weight.
Overall, I think the Shrew I would consistently enjoy the most for "fun" shooting would be a 47 to 52 pound foam core Classic Hunter that I could shoot without fatiguing much and would still have a high enough draw weight to give me that clean release. A Bow Bolt would be nice, but for just fun shooting around the house it would be unnecessary. Same thing with carbon backing. The jury is still out on the carbon backing because I have been sick for most of the month and have not been able to chronograph my new carbon backed Classic Hunter to see what speed gains I get. I don't think the foam/carbon bow is quite as smooth or quiet as my almost identical foam core bow without carbon, so there needs to be a significant speed advantage to the carbon to make it worth adding. I do notice the carbon backed bow is faster, I just don't know how much faster. The foam core Shrews are definitely smoother and faster than the boo core bows. They have a distinctive higher frequency twang until you add string silencers, and then they get very quiet. I must have exotic wood limb veneers though, because I am a sucker for great looks.
I still have another Shrew I ordered a year and a half ago that would already have been built by now except I asked Ron and Gregg to hold off until I decided what I wanted in my next bow. Right now, my ideas are to either get about a 55 pound 56" Lil Favorite with foam limbs and Bow Bolt, or about a 50 pound 56" Classic Hunter with foam/carbon limbs and Bow Bolt, either of them sporting exotic hardwood veneers. I am also on the fence about the carbon backing on the CH until I do the chrono tests.
I know I prefer the Classic Hunter, foam cores, a Bow Bolt and beautiful veneers in a Shrew. I am not sure I answered you question, but I have tried.
Allan