I have one Vokey 54-11 and one 588 60-8 you cannot go wrong with either. I bought the Vokey because I use the 54 for 100 yards and, in as well as for bunker shots and I like the extra weight for those circumstances but the lighter 588 is better for me around the greens.
Cleveland 588 Forged Wedges vs. Titleist Vokey SM4 wedges. - Page 2
Golf Gear mentioned in this thread:
I have 3 wedges in my bag:
50* , 8* bounce - Cleveland 588 Forged, Black Pearl
56* , 10* bounce - Cleveland 588 Forged, Black Pearl
60* , 10* bounce - Vokey SM4, standard finish
IMO the 588 Forged is much better for your game. The other comments made on the thread sum it up - better swing weight, better head with amazing turf interaction, and less mishits overall. Grooves IMO don't matter as much as how much spin you can put on the ball and where you place it on the green, but if I had to say I'd vote for the CG zip grooves as well.
Try both, especially on grass. It'll make a difference on the tight lies, when you have 80-90 yards to the pin and you're lying in the middle of the fairway. You'll know you made the right decision the way the forged 588 clips the turf perfectly and puts itself right in that perfect pendulum. The Vokey will seem to swing lighter and the much thicker sole will be more conducive to bladed or nuked wedge shots.
I keep the Vokey in my bag because it's good out of the sand and I love using it out of the rough for flops around the green, over traps, water, etc...I can still pick it cleanly from the fairway, but only after a lot of practice. It's still a great wedge, but I never understood the benefits of owning a forged club until i got the 588s - my first forged clubs ever.
From the second I started using the Forged 588s, I haven't hit a bad shot with them and they've saved me a good 5 shots a round.
By now you've probably already made the right decision and gone with the 588s, but consider this a bump for newer readers.