1 This may sound silly, but one of the first and easiest things I look for in a Digital player is the silence and smoothness of the tray mechanism.
Then ofcourse the ergonomics. Slim is in. But do check if the unit heats up a lot. The disc should only feel slightly warm after a movie. SOme have built-in fans. Than would be nice, but it should be extremely silent.
2 If you already have a great HT receiver with excellent DTS decoding feature, you won't need one in a DVD player. Otherwise, you'd want one.
3 Having an analog 5.1 RCA output is fairly common now. Also a digital coax and toslink for audio. Many models also sport a mixed-down stereo RCA jack separate from the 5.1 jacks. I'm not sure if generics already have the firewire, d-link and i-link, DVI or HDMI terminals. But many have a VGA termnal which can be great for connecting to a computer monitor screen that has better resolution than regular TV. And an S-video out is also standard.
4 Component Video and Progressive Scan facility with those 3:2 pull-down features I don't really understand is also another common feature. A lot of reviewes are raving about the Faroudja DCDi de-interlacing chips found in a growing number of DVD players. That's another thing to look for. But I doubt if generics have them.
5 I am not really sure how you detect this Chroma Bug in many DVD players or if it can be detected at all when demoing in most appliance stores. There's an interesting net site explaining this that escapes me at the moment. Do a google search on this. Perhaps, most current DVD players with the newer video chips have overcome this problem which was quite prevalent with the early generation DVD players.
6 Upscaling feature that upconverts your 480i DVDs into higher resolutions in component connection is also growing. Am just not so sure if generics have these. This would be a real benefit if you are using those extended or high definition plasma displays. (Though the display often has the upscaling feature already, so maybe this is not important in players.)
7 Rugged construction. In many entry level players, you can feel the spinning motor's vibes when you play a disc by just touching the top or sides. Or you can even hear it whne when you listen close. That shouldn't be. A really good player feels rock solid and is silent. Need I add, they are heavy.
8 Detachable power chord. Many models have this feature already. Can be very convenient when setting up in a rack or if you believe those nonsense about using exotic power chords.
9 192khz/24-bit audio DAC is farily common even on entry levels.
10 54mhz/10-bit video DAC is fairly common as well. Doubling that to 108/12 is found in the more expensive line-ups.
11 Zooming function. Check to see if on JPEG/KODAK mode or Play/Still mode, you can zoom at least 4 times - often common in many generics. Also, make sure there's no annoying zoom indicator on screen that won't go away. Phillips is quite notorious for this.
12 Now that I mentioned it, a DVD player that can play all the known video formats like Divx, Mpeg4 as well as still photos in Jpeg mode (simultaneous with audio) is fairly common.
13 Adjustable video black levels, color saturation and contrast are getting to be common as well but not so sure with generics.
14 Ultra THX certification. I haven't seen any generics with one.
15 SACD and DVD-Audio compatible. That would make your DVD player and Universal player. Haven't seen any generics with this capability. There are some generics with the HDCD logo on the face plate, but I doubt they can decode HDCD, unless you check with an HDCD disc and see an appropriate HDCD indicator on the player light up.
16 Selectible 96khz and 48khz audio sampling rate in the digital out. I guess if you're using older HT receivers than can only accept 48khz in the digital in, this would be a neat feature if you have discs sonically encoded in 96khz.
17 There are a lot of other features like built in equalizers or DSP modes you can select from the player's on-screen menu which I personally find useless, but if you need them, that's your call. Then there are parental lock facilities which I also don't use. Multiple languages, region setting variability, PAL/NTSC conversion, video mode (widescreen, standard, pan & scan) etc. They're pretty much standard on any DVD player.
Just some of the things top in my mind. There's no need to suggest brands or locations as these features are fairly spread across many brands and outlets. Hope this helps.
