Addressing the pros and cons, the obvious things that come to mind seem to work out just as one might expect. The 8-inch gun is awkward, to me. I have trouble shooting the guns as well as the shorter ones, probably a matter of forearm strength. The weight difference is not great, but at arms length, the extra ounces do seem to add up quickly.

If your vision is not the greatest, the extra distance between front and rear sight might not be helpful to you. It isn't for me.

The good thing is the 8-inch gun is by far the mildest of the three, in terms of recoil. I have never heard anyone complain much about the recoil of an 8-inch 29.

None of the drawbacks are pronounced, and the long guns are fun to toy around with. On the other hand, 6.5-inch guns are not hard to come by, and if that is what you really want, why not spend the few extra bucks and get the right one?

If you are buying a gun both to shoot and to "collect," the only ones I know of that are of any particular interest are the ones made shortly after the barrel length was first introduced. But remember, the long barrel attracted quite a bit of interest and some guns were rebarrelled, so buying an early one requires a little expertise to be sure you are buying an original gun, not one returned for service.