The article was almost complete bollocks - yes there is a difference between MF and 35mm DSLR but it's not this 'wine tasting expert sense' thing he's talking about. Here's a list of differences that for me are important
1) Mostly better lenses - however good primes on 35mm SLR can do very well indeed. The simpler the lens design, typically the more rounded the result. Older lenses were designed by trial and error, with designers prioritising 'rendering' as well as resolution. Modern SLR lenses tend to be computer designed. Hence why leica lenses tend to have 'that look'. I have a slight problem with MF wide lenses as the need for strong retrofocus design makes for more complicated lens designs - the results aren't bad but they don't have the relaxed look of longer lenses or LF wide lenses such as the Super Angulons or MF Biogons.
2) Oversampling - not to be ruled out. bayer arrays and the conversion to image data is notorious for making up data. Think of it like the mp3 of the audio world - it works but there is something wierd at low bitrates. However, if you use a really high bitrate it doesn't sound bad at all. This is true of oversampling in terms of resolution in camera sensors
3) Colour rendition - this is the big one for me. In the hunt for better iso performance, manufacturers have been compromising on colour filter arrays. Making them more transparent lets more light in but also lets crossover colour in leading to the debayer having to do more to get the colour back. The Sony A900 is one of the only DSLR's that gets the colours as good as the best MF backs (it beats many, such as the P45)
4) Underexposure - MF backs underexpose by quite a bit by default. This typically helps in the smoothness of tones as you go toward mid-tones to highlights - especially for people who regularly expose to the right.
5) Sensors optimised for low ISO's - possibly this helps when making compromises in chip design?
You add these up and you can see how LF results always had a relaxed and rounded look - MF came close, especially with classically designed lenses and on 35mm you really had to use classic lens designs on rangefinders to get the same effect. (even many modern optics are tweaks of classic designs)
p.s. I did a test recently comparing IQ180 and various other cameras including a Sony A900http://static.timparkin.co.uk/static/tmp/cameratest-2/800px.html
If you look at the top comparison you can compare the IQ180 with the A900 and you'll see that there is very little difference. I personally prefer the A900 colour rendering but they're very close. We used a Pentacon 50mm f/1.8 lens on the Sony A900 which is a good old lens design.
also I have a feeling that the floating optic used in modern auto focus lenses adds significant extra design constraint to lenses - I haven't tested this though so it's just a thought at the moment.