I think the pinnacle is the MFL, or certainly a PFL with a couple of MFL niceties (headlamps, for one) though I know you are a particular fan of the MFL poo-coloured steering wheels.
-The door cards, though overall I think the PFL are nicer, the FL ones do look a quantum leap on in aethetics. Also the concealed little cubbies are a very nice feature.
-The multi-function centre armrest is a feature I like, and means you've somewhere to put your cup! Many people may have forgotten, but 'cupholder one-upmanship' was a definite feature of the 90s, possibly started by the Vectra (which came out 1 year after the Omega)
-Engines which, whatever we think of them now would not pass the emissions regulations of 2001(or thereabouts, forget the exact year) so the Y engines had to happen, restricted in power though they were.
-heated seats with variable temp settings, now that was cool.
Now, before anyone thinks I've turned and become a FL-fancier...
PFL...
-NO rub-off rubberised coatings to make your dash look like it's got dry, flakey skin.
-A simpler engine to work on, with 'proper' HT leads, no separate coil pack thingies, no extra Lambdas to worry about, etc. and the crank sensors are cheaper, too!
-'More practical exterior. I have, regretfully being in contact with walls, posts and other cars, and nice fat textured black plastic is somewhat better at hiding these wee knocks than the 'cracks if you stare at them too hard' FL bumpers.
-Aesthetics - the PFL/MFL Omegas are frowning, sneering, and have a real 'attitude' abou them. The FLs look like a slightly odd replica of a contemporary Audi / Astra G, as mentioned above.
-You can fit your wheels in the boot of a PFL, owners of Elites will know their 235s on 17s don't happily sit in the spare wheel well as we chaps with out 205s
-What is perhaps now forgotten, but one of the most innovative boot handles, copied by numerous car makes now, but a hinged griffin that is the boot release was just so cool back int'daay, lad.