As some people will know, I wasn't too fond of The Office, but I love Extras. Part of it is that Gervais' character, Andy Milman is much more likable than David Brent in the office.
While some people dislike Gervais, say what you like about the man, he sure knows how to surround himself with talent. Maggie played by Ashley Jensen is a revelation, being wonderfully childlike and innocent throughout (and there's some really touching scenes with her in the final episode).
Celebrity cameo's are fun, and work to various extents. Kate Winslet, Patrick Stewart and Les Dennis (who?