A few weeks ago I picked up my first Legacy locomotive, the Polar Railroad GP-7. After using it with my ZW for a while, I finally decided I wanted access to all the cool sounds, especially the two-stage horn. So I bit the bullet and at last am the proud owner of the 990 set. It almost doubled the "cost" of the locomotive, but even my wife came in and listened with an approving nod. Very cool.
I've had a DCS system for a year or two now, and have some PS2 equipment. I think the slow-speed control of the Legacy might be a bit better. I really like the way the throttle dial works (though I really wish it were in thumb range like the DCS throttle), and the LCD keypad is a great touch. Nothing like having context-sensitive buttons!
But the multi-stage horn - it may be weird, but that to me is worth the price of admission. I came very close to buying the Base 1L and just attaching it to my DCS setup, but I REALLY wanted that horn effect. I'm not that into steam, but now I've got a serious lust for the Polar Railroad K4 with the quilling whistle AND whistle steam effect. Bank account, look out!
The bad part about all this of course is that now I want more Legacy iron. On the plus side, I do have some conventional locos I'd like to convert to command use, and ERR seems to provide an upgrade that's rather less than the PS2 upgrade modules, though about the same if you want sound. It also looks more friendly to do-it-yourself installations. I've got an MTH UP gas turbine in PS1 that I'd very much like to get under command control.
That's my report for now. Cheers!
Fred