I just kicked a keg of ESB last night. It was force carbed at 30 psi for about 60 hours. It tasted great, well carbed, and I really enjoyed it.
Tonight, I tried a bottle, naturally carbed, from the same batch. I really didn't enjoy the bottled beer as much as the kegged beer. In fairness, it's only been in the bottle a week, not fully carbed, and I only had it refrigerated for 5 hours. But I tasted the kegged version slightly carbed also and it did taste better at that stage.
As far as taste difference between keg and bottle, I think once my bottles fully carb, and chill properly, I won't notice a flavor difference. I think my dissatisfaction with the bottle was from the lack of proper carb, mouthfeel and the fact I still had yeast in suspension from not properly chilling. More "experimenting" is necessary to be sure