Finally there is some time to answer to this thread:
first of all - I love my B-6!
but, before heading out and getting one, I asked myself if I really needed it (well, useless question for members of this board anyhow but...) because you dish out some significant dineros to get one, no matter which maker;
if you want a jacket that keeps you warm during the worst the weather can throw at you, including rain, snow or other wet stuff, I would go for a N-1 deck jacket; easily as warm and way better in rain and wet conditions;
if you want a really warm jacket that keeps you warm through the coldest the weather can throw at you, get yourself an Irvin or an N-3B Parka; (I have worn the Irvin in temperatures down to -25°C (the doggies wanted out at night during our stay in the Tyrol last year, and yeah it was that cold there..);
advantage of the Irvin is that you can wear it with a light shirt underneath in below zero conditions and it still keeps you warm and comfy plus the Irvin has the best design of all shearlings in my opinion due to its windflap and collar design;
wear one of those rollneck sweaters underneath and you are set for any temperatures below zero you may encounter in Luxemburg; btw, when I did my Cargolux training there in November three years ago, I was happy to have my B-3 and B-10 with me, it was really cold there, even more so on the cargo terminal apron in the open hold of the 747;
before going for a B-6, you may also consider going the Alpaca way and get yourself a B-15A or B-10 (my preference lies with the B-15A due to its better pockets and I like that angled zipper); cheaper, lighter, just as warm and you can move around in a B-15A freely - in my opinion probably the best of the B-series jackets to come out of the war;
well, till now, I have provided only arguments against the B-6
BUT: if you want a jacket that looks great, feels great and can be worn in anything between -5 and +10 (and maybe even lower if you fit some pullover underneath), go for the B-6;
it has the additional advantage that in "higher" temperatures sheepskin feels way nicer than the alpaca lining in B-10/B-15s while lower down, the alpaca jackets work better IMHO;
again, the B-6 can be easily worn in snowfall or light rain, but I would not choose it in a downpour or heavy rain - did I mention that the N-1 is way better suited for such conditions?
FIT: if you want a very trim fit, go one size down from your usual sizing; if you want to be able to wear a sweater/pullover or even your A-2 underneath, stay with your jacket size;
I wear a 46 and this one fits easily over my A-2 (ELC RW27752) or any thicker pullover, giving me some more options when it gets really cold or windy;
AERO vs ELC: having owned both (the Aero only shortly though) I would opt for the ELC; the hide they use on their RW version is just great and the jacket looks awesome; the Aero was nice too, but the I did not like the hide (plus they sent the wrong size) so the decision to send it back was easy;
do not get me wrong: the Aero looked very nice too and if it had been in the right size, who knows; the ELC costs signicantly more now so an Aero might be a good option; their customer service is top notch and you can customize the sizing way more than with ELC, but then again, if you know your measurements and preferences for the fit, it will be easy to decide which size you take and I honestly believe that customized sizing is not necessary...
hope this helps a little bit, if you have any further questions, feel free to ask or pm
cheers from Vienna
phil