A lot of people discuss on this board the idea of improving their chances of being accepted into great universities such as Oxford, Cambridge and Harvard by trying to get great grades in an initial LLM in their home country.

And this is something I'm thinking of doing. But what I'm curious about (and perhaps someone here can shed light on this) is whether a part-time LLM (while working full time) would be looked upon less favourably than a one-year full time LLM. Any thoughts?

I don't believe a p/t LLM as opposed to a f/t LLM will be looked upon any less favourably (especially if you're juggling it with a f/t job).

It's quite a gamble (and cost) to sacrifice evenings and weekends over two years to gain an LLM just for the purpose of increasing one's chance of getting into Oxbridge.