I've been following IF for almost three years now, and I can't imagine my life without it. Of course, my results are anecdotal only, but have supported everything I've read on leangains.com and other sources. For reference, I am 5'2" tall.
I find that IF works incredibly well for me, especially when cutting. I don't even bother thinking about food or considering it when it's not between my eating hours, which frees me up to focus on everything else in my life. I don't have to pack food or find time to eat at work or when I'm busy during the early parts of the day- it's simply convenient, in that respect. I love the carb and calorie cycling (higher calories and higher carbs on lifting days, very low carb/high fat, low calories on rest days) as outlined by Martin Berkhan because once you get used to it it simply feels natural.
I maintain much leaner than I otherwise ever have been able to- and while keeping on muscle as well. I don't find that I have lost strength, even on a cut, with the exception of a few days leading up to photo shoots where my calories were restricted.
This is an older pic- the bottom one was taken last February (this is the results of my last cut), but the differences are pretty easy to see. I started IF right around the time I'm standing by the little palm tree (considered my "starting stats" that I quoted above). Do take into account, though, that I was, and still am, lifting heavy 3-5 days per week. At a maximum, I do HIIT once per week.
IF Visual results
Current, two weeks into a modest bulk, still using IF: