If you're just getting into them, it depends. Are you a fan of Neal Morse? That's gonna be the big factor. Since he's gone the band has changed dramatically. It's pretty much split as to whether that's better or worse depending on who you ask. As far as I know the rest of the band haven't lost their abilities to play. So they should still be able to put on a good show.
Just don't go expecting to hear 'The Doorway' the way it is on the CD. I don't even know if they play anything like that anymore. They might stick to mostly their new stuff and maybe a few old pieces.
See if you can find reviews of the band online as they are now. That could make up your mind.