Love mine.
I suppose it takes bare bottom off the table, if you think you ever want to go there. And from what I've heard they are a pain to catch, if you have to. On a cautionary note, the shrimp may dig under your rock and cause shifts (mine did, and I had to rearrange/reseat my 'scape).
But again, I love the little knuckleheads.
They are awesome together, esp. watching them work, but like Tahoe said, you will have a sandstorm, and as rockhead stated, the combo will shift your rocks, but as long as you understand that they will pull frags into their holes, will cause major sandstorms, will shift your aquascape, then definitely get them. The pair are so much fun to watch, I plan for what they do and then love to watch them as friends. Have fun!!!!
I've never had the sandstorm issue, and I have pretty fine sand. But as to shifting rocks, and snatching frags, small rocks, and extra shells (I keep some laying around for my hermits to move in and out), they do it non-stop. My wife is a GA Tech grad, and we call the shrimp Buzz (their mascot) because he is such a little engineer....
GT! Awesome, we call ours The Wreck, from GT and from his destructive habits. My undergrad was from GA Tech, and I definitely appreciate your stories of the shrimp being an engineer, either it's fun or it's annoying.
final choice goes to who wants it. If you don't mind all of the above, then good. If you want a sterile tank left the way you set it up, then don't..