I've probably met and talked to over 100 MPs over the last 30 years, mostly Labour and have probably seen a good 100 more speak at meetings. I considered myself a personal friend over many years of two Labour MPs in particular - one backbencher who I respected greatly, the other started with some principles but chose to climb the greasy pole and slid down later, still an MP but I haven't spoken to them for years, despite helping them significantly on their way for over a decade.
Met Brown a couple of years ago, while he was still Chancellor, and I chatted with him for a while with a group of others about an aspect of government policy. He was very pleasant, I think he's quite good at small group discussions and very personable especially with ordinary people rather than politicos - my disagreement is with his politics. Had lunch with Frank Field a few years ago and he was totally barmy but quite interesting too. If there was prize for "Off the Wall" MPs he'd win hands down. Have chatted or been in small meetings/committes with many other Labour MPs mostly while in opposition in the 80s and 90s - I knew Robin Cook well as I was on a working group with him that met at the House of Commons frequently, but also Livingstone, Blunkett, Stan Newens, and I'm afraid to say Jack Straw, and probably half a dozen others; spent three hours in a key small meeting (20 or so people) with Tony Benn back in his heyday in 1980s and many other chats. Had lunch with a local Labour MP in the House of Commons a couple of years ago on a sightseeing tour with a local interest group; he's barmy too but quite pleasant. Was embarassed when a local Tory MP came up to me in the Commons Dining Room and slapped me on the back asking how I was and how good it was to see me again (!) - I debated him many years ago at a big public meeting and put up quite a good show, but thought he'd forgotten me. I did have to spend a couple of hours with a very well known slimey Tory MP in the 1980s and was glad to see the back of him - fortunately for everyone he's out of politics now. Chaired a meeting with a local Labour MP and cabinet minister for an interest group just before the 2005 election - both complete Blairite loons who had no idea how to talk to ordinary people and are out of politics now (or will be soon).
I was in London once after the 2001 election drinking with a journalist I know when he invited me to a drinks party called by a Select Committee Chair at the House of Commons and chatted for a long time with a longstanding backbench Labour and LibDem MP both of whom were personable but not very interesting. I was a student with several people who are now MPs - Tory and Labour. Have worked closely with several (6 or 7?) of my local councillors who went on to become MPs later, mostly people with very few principles.
Worst MP I've had the misfortune to meet and talk to/argue with: Jack Cunningham - by a very long way.