I don't think technical differences do tend to be huge (at least not the ones you can measure anyway). Basically you're looking for:
native resolution (unlikely to be different),
response times (probably mostly the same at 17" but irrelevant if you don't play games that involve very quickly moving images),
brightness and contrast (higher the better).
I think a lot of it though is going to come down to reliability of the manufacturer and aesthetics (of the amount and also possibly some screens looking clearer/better than others. So basically read some reviews and have a look in some shops and see what rings your bell!
The other biggy is dead pixels. Most will come with an ISO certification but that doesn't mean there aren't any dead pixels (where one or more of the pixels is permanently on/off). If you can find somewhere that guarantees no dead pixels or will let you look at the screen beforehand it is great but otherwise you'd be relying on distance selling regs to send it back (and when I suggested that to one vendor on a bulletin board he denied it so expect a fight if you try this with most people).
Avoid those that come with built in speakers - they sound tinny and take up space. Also if you are going to be using multiple monitors a thin bezel is highly desirable if you are going to stretch a window across more than one monitor. I use a pair of NEC 1760NX's which have a very narrow bezel and have been very happy with them.
I may be wrong but I believe AOC are a relative newcomer to the UK market so there's likely to be little information on their product warranty available.
Picking up on a point already raised....TFTs do not support the range of different resolutions that CRTs do. As such the default res on a 17" TFT is usually 1280x1024. They can go a bit lower than this, say 1024 x 768, but they usually lose clarity. This may be an issue if you aren't used to the higher res, though it does mean you get to see almost all of those lovely charts people paste on T2W without needing to scroll :~}. A reasonable CRT/graphics card combination would support anything from 800x600 up to 1600 x 1200 and often more than this.
One other small point is that many TFTs don't have a height adjustment - check if this matters.
Currently running a Philips 170S2 at work which is decent piece of kit.
YO Bonsai.. howzit going??
I would get one with fast response time <25ms and one which has high resolution (you'll find a lot of the cheaper TFT have a max resolution of 1024 x 768).
I think PC format magazine did a feature on flatscreens.. the Vobis 767 looks good and decent priced. There was a Sony which was really good too..
Just remembered last night one of the more important differences to be aware of/look out for - DVI vs. analogue. Digital is meant to be clearer if your card supports it and I think most DVI's will take analogue as well but you should check. DVI is almost always a premium so if you're using a card/s that don't support DVI its probably a waste getting a DVI monitor (save that it would allow for upgrading and your monitor/s will almost certainly outlast the usefulness of the PC).
taken on board most of the advice.
Decided on NEC 1701. Good response rate, neat looker
and no DVI and no speakers.
Arrived today, in use and that's when the first problems started.
1)Was previously using CRT with resolution up to 1280x1024
When I plugged in NEC and adjusted to this resolution, got
big bad error message "Video Input out of Range" and nothing
responds. So back with the CRT change the settings back to
1024x768 . Plug NEC back in and all OK.
I moved it up to 1152x864 and all seems OK.
But I really need the higher resolution. Does anybody have any
RogerM, are you our NEC expert ?