Granted, I just dabble in audio, but I'm surprised you're using Windows in the first place. Fully anecdotal, of course, but everybody I know runs OS X with one or another setup (Live or Logic, depending). I do audio more for podcasts and the occasional composition and Logic Remote on my iPad (an old iPad 2) is a really solid touch surface with surprisingly low latency.
iPad only has toy DJ apps, it doesn't allow remote playlist control or really anything useful that compares to having the full OS as a touchscreen.
Also the iPad is more fragile, twice as expensive, and has a fraction of the storage for audio, compared to my Asus ultrabook. I only use the iPad in the studio.
It's much cheaper to get started on Windows, the plugins and programs are vast and often free compared to the Mac equivalent. The majority of my stuff also works on Mac but I'd have to relearn my workflow.
I do have a Mac but using it feels like I'm in the office compared to Windows touch experience. As an app dev I'm always trying to push the boundaries in music interfaces.
To clarify: the iPad acts as an interface to the DAW, not as a DAW itself. Either Logic Remote or the OSC-based equivalents are really nice ways to drive applications (touch-based mixers, etc.).
Right, I use several of the controller apps myself and send OSC or MIDI. It is a complex, less intuitive, more fragile, and less useful setup than having one machine that can do everything with touch. In the studio, where nothing changes, this is less of a problem.
