You're not really comparing apples and pears here. I have no doubt that the LE jacket will be fine for general cold weather use, pubs etc, but for any sort of technical use the Rab jacket will be warmer, much lighter, better thought through etc. LE uses 80 per-cent down fulling, the LE one has 96 per-cent down, etc.

If you're after a decent technical down jacket at a reasonable price, the Alpkit stuff is great value.

I have an old LE reversible hooded down jacket - the slider off the sip broke off a long time ago but otherwise its been pretty good.  Never been tested in anger but has been worn horse riding in the UK, and also out in the wilds of Iceland though under a heavyweight shell.  Size ladies M it weighs 740g.

I bought an LE down jacket 4 years ago in their sale, I think for about 30 quid. Its fine for street wear and I have worn mine on skiing trips but there's nothing technical about it and I have now replaced it.