I've got 3 7-strings: a 1527, a 2027 and a 1077XL.
I've got to say the 1527 is awesome and holds it's own when compared to my others, the neck is fantastic and I've found the EdgePro bridge to be just as stable as the LoPro. The only downside is that it doesn't exactly have the most varied of colour options.
It replaced the 7620, and while I've never tried one of these, I understand that they're pretty comparable. The advantages to the 7620 are that they have the allegedly better LoPro bridge, they have a more varied colour choice, and of course they are much cheaper. However the 1527 has a Prestige neck which, as I say, is superb.
Let me put it this way: my 1527 converted me to the ways of the 7-string Dark Side
