Is it specifically a fleece you are after? If you are just after a goood warm layer you could go for something like the Rab Photon smock which is a synthetic-filled pullover (thin layer of Primaloft PL1 insulation) – lighter, much warmer, and more windproof than the vast majority of fleeces, and much less bulky than duvet-type insulated jackets. It layers up well too (I'm a fan), and is reasonably priced. There are other really good synthetic-fill offerings out there too, one from Montane (the Solo I think?) is often given an excellent write-up. And the warmer, but heavier Golite Coal is also supposed to be very good, but I've not tried either of these myself.
Erm, nope. I've the patagonia R2 and it's toasty and packable but is as windproof as a wet cotton t-shirt. But couple it to a pertex windshirt and it's excellent. Having the fleece and windshirt as two separate layers gives you more versatility too, IMHO.
And how high? And what are you intending doing? Walking, climbing, riding on a donkey...? ;-)
Agree completely with RW - windshirt & fleece more versatile than windproof fleece. Also likely to be lighter, cheaper, more water resistant and less bulky.
I assume the R2 and Monkeyman links didn't come up by magic? In which case, yes, the R2 is light and warm, but not at all windproof. Since the MM is also ThermalPro, expect similar behaviour.
If you're really set on one of these, have a look for a Sprayway Zone 2: £40 in TK Maxx at the moment (well, in mine at least). Same style and fabric. I picked up my R2 jacket & pullover in TKM for £27 and £17 respectively).
The synthetic duvets are very warm for weight and bulk, but have two layers of Pertex, so don't breathe as well, and you can't cool off by removing the windproofing. Excellent for static warmth, though, such as evening camp, long stops, belaying, etc.
If cold and wet a synthetic duvet would be great, but quite heavy. A thin synthetic pulover needn't be over 450g, lighter and better than almost all midweight fleece IMHO. But I'd also give a big thumbs up to a thin fleece and windproof combo too – I agree, depends on how cold it is and what you're doing. I love my pertex windproof, so versatile.
Not sure about duvet being heavy - my Montane Solo (small) is 368g, and the Krypton pertex/microfleece smock is 398g. A 100m fleece and pertex windshirt will come in at about 400g. Guess it depends on what you mean by 'duvet'...
Yup, apologies for not being specific with my terminology. Personally I would not class the Montane Solo or Rab Photon as a 'duvet', but as synthetic-fill pullovers. I'd reserve the term duvet for the thick puffer-type jacket things you'd only really need (outside of a harsh winter) in camp.
I don't think you necessarily lose versatility if you carry a syn-fill top, just carry an ultralight windtop too (70-90g from Rab, Golite, Montane etc.)
For 3 season I usually carry the 370g Rab Photon and the 86g Montane featherlight windtop (~450g total weight). I used to use the really pleasing (but much less versatile and much less warm ME Guide windproof fleece) weighing 610g, and I'd still need to carry a thin fleece as back-up warm layer, so new my current line-up is barely half the weight for 3-season hill use. The ~350g weight saving may not amount to a hill of beans on a day walk, but my dodgy knee thanks me for my consideration when backpacking.
Anyway, sorry to bog down the debate with my twaddle...