Ok, there's just a problem in your set-up. There is nothing wrong with the Edge when it is set up properly, which is mostly the reason why everyone says it sucks, because theirs isn't set up right. It is however, harder to set up perfectly. This is no reason to hate it though.
In the basics of any tremolo system, you have two forces on the tremolo.
1. The tension of the strings
2. The tension of the springs
These forces need to be equal as everyone knows, which is why you can't just simply unlock it and go into dropped tunings, but a lot of times when you adjust the tension in the springs, you'll over-do it or under-do it by a hair, or in some cases, the tension of the strings will change over time.
And even though the trem may look balanced, it isn't. Edge 3, and most other bridges, including Floyd's, will stay put when it's near balance, meaning it won't drift to one side or the other, but it will not stay in tune however. But different trems are more/less sensitive to this than others.
Floyd's are more stable, meaning that you don't have to be as close to equilibrium for it to stay in tune. However, there is a compromise. Floyds tend to be larger, and have more sharp edges in my opinion. In most guitars I've seen w/Floyd, the cavity isn't that deep.( That more has to do with the actual guitar, but I'm just sayin') And it's a little bit more trouble to change strings than an Edge bridge.
Edge's however are sleeker( at least the newer models), more compact, but are more sensitive to the equilibrium than a Floyd Rose. That is why they tend to go out of tune very easily when they aren't in equilibrium. But, once you get it there, it is sincerely marvelous. Edge model bridges are more sensitive to subtle movements, meaning they will change the pitch with less force from you. Ibanez guitars( from what I've seen) tend to have deeper cavities as well.
Now the difference between Edge3 and Pro comes in at two points mainly. The string changing, and the intonation point. Edge 3 is easier to change than a floyd being that everything is right on top, nothing is really poking out of the back, and that saves you a little time having everything right in front of you, esspecially when tightening new strings in. Edge Pro is by far the best Edge out there. You don't have to cut the ball ends, and none of the blocks that compress the strings can fall out of the guitar(which I found out just recently). But most importantly, the sound metal chip increases sustain at the intonation point, and who doesn't love more sustain right? And if you are wondering, the Zero bridges are alot more stable, but don't feature the ball end accomodation or the sound metal chip, but they are more easily adjusted than a floyd. I hear there were some limits on the maneuvers you could do with it, such as flutters...but I haven't played a genuine S series in a while to remember.
When a double locking tremolo is off-balance( with more tension on the springs), the springs will pull the trem back, and if the strings don't have enough tension on them to keep it from recessing back into the guitar, the mere length of the strings will. When you pull back, you're adding tension to the strings,and you're releasing tension from the springs. The strings stay a half step sharp because the tension on both sides wants to return nearer to equilibrium, which made the trem stray closer to its balance point, thus putting more tension on the strings, thus making them go ( and stay) sharp.
Also, as a quick tip, if you forget to stretch your strings beforehand, they can stretch and cause problems with the tension later, so always do that before balancing your trem. In other words, make sure the strings are stable before you go and start the balancing, or else you will have to fix it.
To get a true sense of where the tensions are balanced, unlock the top and just let it loose with the whammy. Keep tuning it back up. Repeat, and you will see the trem drifting to one side. After multiple times of tediously tuning it back up, the tension should be at equilibrium. That is where you COULD lock the nut, use the whammy and have it stay in tune. Odds are that if it drifted to one side, you're not happy with where it is. THAT is when you go to adjust the spring tension.
After adjusting the springs a little, go crazy with the whammy and see where it goes, and eventually, with a little work, you'll be able to get it to the point you want it to be.( I keep mine a little high so I can pull back further, btw.) Also, you'll get more of a feel for how far the trem with go when you adjust the springs, which will save you time later.
That should sum it up nicely I believe. Now if anyone here has questions about double locking tremolo systems except for Kahler and TransTrem systems,( I have no experience with those), feel free to email me at firstname.lastname@example.org
. I will be happy to answer your questions.