Feature:
The most useful feature in the Privia PX-320 is the registration memory. Given only a simple 3-digit LCD display, patch numbers for individual tones may be difficult to memorize. However, with the registration memory, you can store any favorite instrument tone (layered, or non-layered) as well as many other keyboard settings (keyboard split-point, brightness settings for the piano, reverb/chorus effects, rhythm accompaniment style, tempo settings etc.) The next useful feature is the LINE-OUT ports (L & R) which is handy for connecting the PX-320 to loudspeakers (e.g. PA system, monitor speakers, keyboard amps, or even a simple Stereo Hi-Fi Component system with AUX-IN). This is important for gig musicians who regularly hook up their gears to loudspeakers during performances. Another useful feature is the 2-track recorder feature which is good for recording music ideas/arrangements or simple keyboard/piano performances when you feel like recording on-the-spot MINUS the need for the PC and recording softwares. And I certainly appreciate the 16-channel multitimbral General MIDI compatibility of the PX-320. Sending and receiving MIDI is I wish the PX-320 had a pitch-bend wheel (useful for guitar patches). A larger LCD display (colored or monochrome) would be very much appreciated although during live stage performances or gigs in clubs where lights in the stage are "dim", the red 3-digit LCD display is more than sufficient to be seen by the keyboardist clearly...based on my experience. I wish there was a brass slide patch, however, which is often used by real brass players to add "style" to their playing. But the lack of brass slide is only a minor matter, as you could always have this by connecting the PX-320 to a good sound module and/or VSTi-equipped laptop which you can easily bring along with you during gigs. I also wish the PX-320 had a "bass guitar slide" patch that can be handy when making home recordings, arrangements or even during live performances (on a keyboard-split mode) when you lack a bass guitarist who can do those "slides" and add flavor to the song your playing/arranging.

Quality:
I've only had the PX-320 for 4 months but I've been using it in gigs with my band 3 days after it arrived (I still had to familiarize myself with features and function buttons prior to using it in gigs for a "trouble-free" use during live performance of course)... It has been reliable and rock-steady so far. and I haven't experienced any problem with it yet. It seemed to be holding out quite well so far considering I've been moving it around and using it in gigs. The keybed seem to be handling several hours of practice everyday...so far no problems in this regard. I've probably be extra careful when carrying it around so as to avoid bumping the side panels of the PX-320 since these are made of plastic and can be dented or broken if hit hard on corners or walls.

Value:
It's worth the $700-$800 price its currently being sold at in different stores (depending on whether it is packaged with/without C65 wooden stand and pedals). This is simply one of the best digital pianos with good "price-to-features" ratio.

Desirability:
The PX-320 is not bulky...which is actually good for gig-musicians having to carry it out on gigs. The external design is rather "minimalistic" and simple. The 3-digit LCD display may be disconcerting for others...but when I'm carrying it around, at least, I wouldn't have to worry about bumping and breaking a larger, touch-screen LCD displays that more expensive digital pianos have.

Sound:
There are 2 "main" grand piano patches in the PX-320: The "MODERN GRAND PIANO" (which has a slightly brighter sound, "non-muddy" full bass sound on the lower register and "sparkly" sound on the higher registers) and a "CLASSIC GRAND PIANO" (which has a softer, more gentle and tempered sound but still has a rich, deep bass sound on lower registers and "delicate" sound on the higher registers). Personally, I use the MODERN GRAND PIANO patch for pop, dance and rock music during gigs since it has more "kick" into it. The CLASSIC GRAND patch I use for playing classical music when I'm at home and for certain ballads/love songs that our band may play during gigs that don't require a powerful or bright sound but a "mellow"/"soft" one. You can fully appreciate the excellent decay and resonance of each note played when using headphones or when connected to loud speakers. There are many other variation piano sounds in the PX-320 (some located in the Various Tone section and some in the GM section). To mention a few, it has L.A. piano, Mellow piano) There are decent EP sounds (60's EP, Dyno-EP and 2 others I can't recall at the moment) and some decent, if not good, useable organ patches as well. The brass ensemble patches are fine (the saxophone patch could use more samples and improvement but they can still be fairly useable on certain songs).

Ease of Use:
The interface is simple. There are several dedicated function buttons and instrument tone buttons on the control panel. To access other tones (there are 202 built-in instrument tones), you need to press the "Various Tones/GM tones" button while pressing the "YES/NO" button to scroll up or down the instrument patch list. This may be a bit disconcerting at first, since you see only the instrument number and not the instrument name (you may have to memorize the patch number of your favorite instrument tones). Changing/shifting from one instrument tone to the another is handled EASILY with the use of the registration memory. Recalling your favorite instrument patches also is made easy using the registration memory features (there are 96 registration memory banks which you could use to store various keyboard settings I've mentioned above/earlier.

Support:
I've e-mailed Casio customer support when I was inquiring about the PX-320 twice and response came in within 24 hours from the time I sent the e-mails. I've e-mailed them again recently giving them some "feedback" on how they could improve the functionality of their digital pianos and they have been more than receptive and even encouraged me to send them suggestions as to features or how they could improve their products in the future. Response came in within 24 hours again. (In that e-mail, I also gave a negative feedback of Casio's older PX-575R/PX-410R digital piano which lacked good polyphony and dedicated LINE-OUT ports which didn't make it "gig-friendly" or multi-track instrument-friendly. THANKFULLY, the PX-320 has 128-note polyphony and dedicated LINE-OUT ports!) I'm yet to experience problem with the PX-320, and so I couldn't fully assess their after-sales customer support...for this, I'm holding out on giving them a perfect score.

Overall:
I'd probably supplement it with a good sound module to add better strings, some brass instruments (particularly saxophone patches)