On the other hand
, a hand surgery rotation, particularly at an academic center, will likely have a large variety of cases, from trauma to congenital to carpal tunnels and trigger fingers. Certainly more interesting than doing the same case 5 times a day. And nobody will expect you to know much beyond basic anatomy, and there's an opportunity to really show your smarts if you did read about the case. As far as getting to do stuff, as a medical student you're unlikely to get to do much beyond skin closures, and you'll probably get to do that on hand as well.
Also, you probably will not have to round on too many patients on the hand service (hence no waking up at 4am), but you might be able to show how hard you work in the clinic.
From personal experience - the most I got to do on joints cases was close skin and subcutaneous tissues, and had to stand around holding the leg, which sucks. But I also did a hand rotation, and saw cool cases, drilled / put in screws for DR fractures, poked around a wrist with a scope, and injected trigger fingers in clinic - overall a much better experience for a med student.
Still, the most important consideration would be the prominence / importance of attendings you would work with, and whether or not you would be working with a chief resident - they are the ones making decisions on applicants.