Either Iscore or gamechanger for us. You do have to make sure Ipad has enough charge and be ready on really hot days if it shuts down. In rec I would use paper as we changed positions a lot.
DD's team uses either GC or a paper book. It seems like every game I attend they use GC, and coaches wife runs it most of the time. Every game I have to miss and it's driving me crazy wanting to know what's going on, they tend to use the paper score book lol.
My wife has been keeping score for me (baseball and softball) for 15+ yrs. So it's a paper book always. Little notes on the sides to give me the players batting 2-3 and such. Might have to switch over sometime when I want better stats but so far that's what I have always liked.
GameChanger since Spring of 2013. DD is off to college, I am still an assistant coach and do gamechanger for her last team.