I have experience with these tires and was actually going to start a thread but never got around to it.
All Weather tires are not that new really, at least I've had mine (Nokian WRG2) since 2010 and they weren't completely new back then (I see from your link there is a WRG3 out now).
We lived in Vancouver and wanted something to get us up Mt Seymour (with chains in reserve) for our 2007 Camry, and the fact these tires can be left on all year around (esp in Vancouver's summers which are not extremely hot) seemed ideal, so we swapped the OEM Michelin all seasons (can't remember the exact model) for the Nokian WRG2s. I was astounded how good these Nokian tires were. Driving in the pouring rain was like being on a dry pavement while other cars were slipping and sliding. After moving to Toronto still with the Camry they performed equally well in the snow and ice here, and they were fine in summer as well.
In fact these tires were so good, accompanied by my hate of the twice-yearly changing tires ritual, that I resolved even before we purchased our GS350 that these tires were going on the GS.
So three weeks after purchase (October, so a little before the really cold weather) I took the car to Kal Tire where they removed the OEM Michelin Primacy MXM4s and replaced them with the Nokian WRG2s.
What was immediately noticeable was how good the MXM4s that I'd discarded really were. They are superb in the wet (at that time of year anyway), give a lovely smooth ride and are extremely quiet.
The Nokians on the other hand give a somewhat harsher ride, and the noise on highways, while really not a cause for complaint in a 2007 Camry, suddenly seemed off putting in a refined vehicle like the GS.
I took the car to the Lexus dealer to get the wheels road force balanced and this improved matters greatly. Got through the winter no problem (these are great tires in wet, cold, slush, ice, light to medium snow) but once the spring arrived I found myself missing the MXM4s more and more and by the time summer had ended I'd decided to repurchase the MXM4s (!!), which I did, with the intention of leaving them on all year around (since I hate doing the tire swap thing as mentioned), however after being burnt once already I retained the WRG2s just in case I changed my mind yet again.
The upshot is the WRG2s while certainly "All Weather" are really more accurately described as winter tires that can be left on all year round. They perform at their best in fall, winter and spring, so I'd class them as 3 season tires myself (but which can be left on in summer if desired).
I'd also class the MXM4s as 3 season tires. Yes they have the sunflower oil that softens the compound but they really are no match for the WRG2s in winter.
So, I use both sets of tires now - the MXM4s from around mid March to late November, and the WRG2s over the harshest months.
While obviously this does mean the added expense and inconvenience of the twice-yearly change, it does give the best all round driving experience, for me anyway - plus there is such a big weather and temperature overlap between the two sets of tires that it is no issue to hold off longer or change them earlier rather than second guessing when the weather is going to warm up and when's the best weekend to make the change, etc. which a lot of people fret over.
Hopefully the above gives some idea of the relatives merits of each. Oh, I haven't mentioned cornering. They both corner the same (really well).
Wow what a rant that was, hope this is of mild interest at least