Hi Joe.
I've had an ESP Ltd M302 for a couple of years. It's pretty similar in spec to the KH602, except without the active EMGs. It was roughly £800 new.
Before I bought it, I checked out numerous ESPs, including several of the cheaper models. It is definitely worth going for a slightly more expensive model.
The difference in playablility and tone is certainly noticeable, as is the detail in the finish. The fretwork, for example, on mine was perfect straight out of the box, but some of the lower end models it would have needed some work to take the sharpness off the ends and level them off.
Pickup -wise, while mine has the passive EMGs, I played several with the active EMGs (which were out of my price range), and they sounded pretty good, but not as good as I expected. I had my local repairer install a set of Warpigs in mine, which made it sound, to my ears anyway, better than the active EMG equipped models.
Anyway, I hope this helps you out a bit.
P.S. If you're interested, my ESP is currently for sale. I had the same repairer put the old EMGs back in, as the Warpigs are going in anthother guitar.
Please see
http://bareknucklepickups.co.uk/forum/viewtopic.php?t=6827 for all the details.