I replaced my Apogee Duet 1 (Firewire) with the iD14.

The Duet was very bright. I have listened to far better interfaces than those two and the Duet was far brighter than neutral, both on inputs and outputs.

The iD14 is less grainy, although possibly slightly more distorted in what sounds like an "analogue" way. The preamps and DI sound fat and musical – my Duet's preamps sounded weedy and pinched in comparison.

The best AD/DA you will get for a lowish price is the UH-7000. Better than both of these. However, I would prefer to track with the Audient because of how weighty and musical the preamps sound – nevermind the much lower price.

To go up from the Tascam you'd have to spend big bucks. I'd say neither the Babyface nor the Apollos are any better. Higher end RME or Apogee might be better, but we're straying from the price point.

The big boys would be the Metric Halo ULN-2 and Prism Sound Lyra, maybe Lynx Studio Hilo.