Pros: Distance, durability, spin
The e5 is designed to fly higher than a typical ball. I didn't notice any ball flight difference in my short and mid irons. I did, however, notice that my ball flight on flush hits with my hybrids and driver would peak a little higher and I got the impression that their total distance was a little longer.
Being a two-piece ball, the e5 had a solid feel off the tee and with my long clubs -- not too hard, but not soft either. Definitely not the feel of a 3-piece ball. Off the putter, it felt a little hard and sounded a little clicky. The e5 is definitely not a soft ball, but it's not a rock. It's somewhere comfortably in the middle, but not as soft as the Gamer v2.
Since the e5 has a urethane cover, I was hoping for some good wedge spin. I was not disappointed. I once hit a 30 yard pitch over a short tree onto a downhill green with my 52* wedge opened up a little bit. The e5 only rolled out 8 to 10 feet. It wasn't even a great pitch (I hit a bit fat) so I was impressed that the ball held onto the green as well as it did on a downhill lie. I had a couple full PW shots that only rolled out 6 or so feet. I think that it matched the Gamer v2's greenside spin, if not slightly exceeding it, and is probably as good spin as a ball will get for under $30.
I was impressed with the e5's durability. I was afraid that the urethane cover wouldn't fair well in wedge play, but it turned out that I had nothing to fear. I played the same ball through 9 holes on a pitch-n-putt course (a bunch of full wedge and half wedge shots) and didn't get a scratch on it. I don't hit the spinniest of wedge shots, but between that and the few holes I used it for on the next full course I played, I was impressed to not see a single scratch show up. It's a little more durable than the Gamer v2.
Overall, compared to the Gamer 2, I felt like I got a little more performance for a little more money. At the same price, I'd go for the e5. At an extra $7/dozen for the e5, it's kind of a toss-up depending on how many balls I anticipate going through.