I'm a big fan of the Winslow ligature (I use one on my Meyer 6 alto mpc), but they're hard to find nowadays . . . It depends on what you want sonically . . . ligatures like the Olegature will compress the harmonic spectrum--granted, you will have good control. Others, such as a Brancher, Francois Louis, etc. will give you a broader harmonic spectrum but will sacrifice that control. The Bonade and the Vandoren Optimum are good middle-of-the-road options (the Optimum offers a variety of tone plates with which you can experiment). I've heard lots of good things about BG ligatures, particularly the BG Tradition. I wouldn't recommend a Rovner as that will deaden the vibrations of the mouthpiece too much.