They had an Apogee Duet.
All aluminum and no display, only led meters.
Then they came up with the Duet 2, which was black and aluminum IIRC, with a display.
They still sell it and call it "Duet 2 for Mac".
Then they came up with what I suspect being an USB class compliant Duet 2, looking just the same as the Duet 2.
That's what they call "Duet 2 for iPad & Mac".
The last two sound the same, though the last one works with iPads.
If it's a Duet 2 what's on sale for $350 and you feel like you'll not really need to record stuff on iPads (which trust me is hella more convenient for field recordings), I'd buy it - it's a good price.
If it's a Duet (first gen, firewire) that's on salt for $350, don't get it.
You can find that for waaay less money.
I reckon the problems you're talking about were hardware problems related to the shiny apogee stuff generation - the Duet and the Ensemble, which started having all sort of problems after OS X 10.6 IIRC, so you should be fine with a Duet 2, be it for mac only or for iPad and mac.