I've been shooting a Spencer in 44-40 for about 3 years in monthly SASS matches. It's accurate and very reliable. I will say that, once you get one - new or used - tighten every screww you see. In addition, mine is a little picky about OAL so you may have to experiment.
For the money, I don't think there is a more fun rifle to shoot that's legal in SASS, NCOWS and GAF. Of course, you won't break any speed records.
Sgt. John