I personally think that it is a matter of choice whether you would like to use it or not. I'd say "Much appreciated" is a casual sign-off that should be used for expressing gratitude for favors, like trying to confirm with someone to be a reference for your letter of recommendation or basically asking of someone to do a favor, like babysitting, housekeeping, etc. and once the favor is accepted ... More @Wikipedia
Get the latest news about Under-appreciated from the top news sites, aggregators and blogs. Also included are videos, photos, and websites related to Under-appreciated.
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.