How long did going through this book take you guys, I have heard how many of the problems are "easy" but what exactly is easy, seeing it on sight? I'm only 150 problems in but it feels like its taken me a while to get this far, been reading for about a week now.

I bought it around 12k, and I'll finish it... someday. I mostly just pick it up and do a few pages when I have time, and often I lose my bookmark. However, I'm bad at tsumego, and don't really do books very systematically.

_________________
Someday I want to be strong enough to earn KGS[-].

I would say it took me at least 3 months, but I wasn't trying to finish it as fast as possible. I would just do some whenever I felt like it. I read it when I was in the 5 kyu range I think. The 5-move problems are definitely quite challenging, some I would spend 10 minutes on a single problem.

I went through once, but over a period of half a year (~9k-4k), I think ^^

At my "peak" I solved 88 5-move-problems in nine days. The first two hundred or so, I'm now able to solve within a day, within an hour and a half, I think.

My experience is, that being able to solve "1001-Life-and-Death Problems" has a lot to do with getting used to it's problems and how they are presented. In the end, there are almost only shortage-of-liberty problems and when you solved the first ten, you'll get used to it.
Same goes for the beginning, if I remember correctly the first hundred problems all deal with a handfull of similiar moves. The vast numbers are only to internalize these moves.

_________________
My "guide" to become stronger in Go

I started 1001 L&D Problems as 8k in July 2009 and it took me three months to do 830 problems (around 10 per day on average). I did the last 170 last August (at 7k). The one and three move problems are fine, solving percentage about 85%. The last 300 are much tougher, the solving ration dropped to about 65% (which is quite frustrating). Some day when I am around 3k and have read some other L&D books, I will pick it up again and want to compare the result to the past results.