We played 4E for about 2 months. We had two different DMs run us through Keep on the Shadowfell, an RPGA DM run us through a Living Realms adventure, and another RPGA DM run us through a 10th level tournament adventure. I would say our experience was pretty much as all-inclusive as one could get without playing with the actual designers at WotC.
My personal turnoffs from the system are...
Potential solutions are in blue text.
1) Basically there are 4 characters: defenders, strikers, controllers, and leaders. There are two flavors of each. Other than that, you end up making the same character again and again. I was getting bored with character creation by the time I made my third character.
New books will come out to give more options for character creation. DMs can create new character classes. Players can make their characters unique through role playing.
2) The combats dragged on forever / gameplay was boring.
I heard that if you decrease each enemy's hit points by half and don't use solo monsters you can speed up combats.
3) After you use a daily or encounter power, every subsequent round feels the same.
The DM can make things more interesting tactically by changing the battlefield or changing the tactics of the monsters. Players can attempt to grapple or use other combat manuevers.
4) It is a tactical skirmish game. The game breaks down if you try to apply the rules in non-combat situations.
As long as you're okay with the limitations of the system this shouldn't be a problem for you.
5) The board game feel doesn't suit me. I cannot see scheduling 4 hour blocks weekly to play Monopoly. Yet, 4E has the same level of depth.
Again, the answer is same as #4.
6) I don't like the way the product is designed with installment plans of the Core Rulebooks. (Unless WotC plans to reprint the rules each time, things are going to get confusing for retailers, distributors, and new gamers.)
Then I realized, I don't have to buy everything.
7) We were already familiar with 3.5, already owned the books, and we seemed to like it better than 4E.
So we decided to stick with 3.5. If you don't already own 3.5 and you can't find used copies of the book (or don't want to get the information free online through the SRD), then 4E might be the game for you.
8) No one around here likes 4E, so you couldn't find gamers to join a group of 4E anyway.
Once (if) the online tabletop is ready, a 4E might be able to find a group online.
Retreater