Personally...
1. Above all, "decent" sound hardware and enough memory (or expansion) to hold my music collection in lossless.
2. Easy-to-use interface - this probably dictates a touch-screen and a music app that indexes your collection intelligently, usefully and comprehensively.
3, Comprehensive output options, i.e. headphone out, line out, digital out, bluetooth aptx.
3. Android-based and GPS are a huge plus but not a necessity - this would open up the complete world of apps and, in particular, allow the unit to be used as a satnav in the car as well as music player.
4. The step up from "decent" audio to "audiophile" is again a huge plus but not a necessity.
5. At a superficial level, a premium case (like the ZX1), but again not essential if everything else was perfect.
The F886 looked *almost* feasible, it has hi-res audio capabilities like the ZX1, but with 32GB which is not expandable it's not worth the asking price for the hassle of choosing which 15% of my music collection I'd like to be limited to today, and then downloading it. (I have around 160GB of music currently in FLAC format, which I don't think is particularly large for a reasonable music collection, and I haven't even digitised my vinyl yet!)
I was very attracted to the ZX1, it looks gorgeous. But at £549 it started to look way too expensive given I'd still have to store my collection on it in MP3. I thought it quite odd that Sony would advertise it so heavily for playing hi-res music when you'd have to save it as MP3 if you want it to hold a reasonable chunk of your collection. And of course, your collection will only grow as hi-res becomes more common. I wrote to Sony actually, giving my misgivings, I've been waiting almost 2 years for a new, improved version, lol!
I also have a bee-in-my-bonnet about browsing structures in music apps. It's very difficult to find an app, whether iOS or Android, that doesn't completely mangle your neatly and meticulously catalogued and tagged music collection. The difference between Track Artist and Album Artist is one of the most fundamental things that they get wrong. And going into a Genres menu, choosing Blues for example, and being presented with a list of a couple of thousand tracks is absolutely useless. Cataloguing, browsing and searching is as much a part of the audiophile and music enthusiast experience as sound quality is. But this is all software, it should be really easy for companies to listen to suggestions and make continuous improvements to hardware that people have already bought but they rarely do in the case of ease-of-use of music apps.
Anyway, none of this (apart from the audiophile hardware) is nothing that you wouldn't already expect in middle of the range Android phones, even cheaper ones, and they have the advantage of being used as phones as well!
I think probably the biggest sticking point so far with any device has been the limited memory. The ZX2 does appear to be standing out in that field at the moment, because it has a decent internal memory and also an expandable slot that can also take a decent amount of memory. I would expect to pay between £300 and £400 for a reasonable Android device with enough memory. If the ZX1 had been improved to the level of 128GB expandable memory, a more recent version of Android and a better screen then I'd probably stretch to the £549 that the old model was, or I'd buy the F886 if it too had the better memory. Just compare this with the prices of Android phones and iPhones.
I really, really don't think I'm being unrealistic. Maybe the audiophile components of the ZX2 do raise it to a higher level that I don't actually need and am not willing to pay for, however there is nothing below it that has the memory. I was also particularly disturbed when a reviewer of the ZX1 on Amazon (who was obviously an audiophile) gave it 5 stars but also said it's a waste of money unless you use a pair of expensive high-end headphones with it. In other words, unless you do already have expensive headphones, you are not likely to hear any improvement over any other MP3 player.
Sorry for the rants, lol! I just felt very very disappointed and deflated after lusting after the ZX1 for so long but realising that it's not going to be practical because of the memory limit, and then finding the replacement is £1000, putting it into realms that even I can't justify spending on a gadget.
