Kindle Unlimited??

To use Kindle Unlimited, or not?
I've read so many different takes on utilizing Kindle Unlimited. For my first book, Bloody Beginnings, I decided to enroll right away. For those who don't know, Kindle Unlimited is an Amazon program. For a monthly fee, people enrolled in the program can borrow enrolled books for free. Since it was my first book, I thought I should try it out to potentially reach more users.
You must sign up for 90 day periods, and here's the real catch... You can't sell your e-book on any other markets. You must be exclusive through Amazon.
As with any program, there are good things, and bad.
Sales- You have the option, during each 90 day enrollment period, to put your book "on sale", utilizing the Kindle Countdown Deals. This puts your book in an extra search engine, for those looking for these deals. During my first 90 day period, I utilized this, making my book $0.99 for the full 7 days. My results were less than satisfactory. While I did have a good jump the first day, my sales trickled in the rest of the time.
During my next 90 days, I decided to try the Free listing. You can pick any five days during your 90 day period to put your book free. The first time I made my book free, I had a HUGE jump! I didn't do any advertising outside of Twitter and my website, but the results were fantastic. I reached the best-seller's list for Paranormal Fantasy (top 100 free). Even after the sale ended, I had quite a few paying sales, but after a few days it trickled off once more.
A few weeks later, I tried the free day again. Sales were minimal. I did two more days, consecutively this time, and sales were slightly larger, but still nowhere near what they were that first time.
Part of the problem with the free days, is that your book leaves the paid category to go to the free category. When that happens, your sales rank drop drastically.
I'm coming to the end of my 90 day enrollment period, and I think it's time for me to branch out beyond Amazon. Amazon recently changed their structure with KU, and I find it fascinating seeing how many pages of my book were read instead of how many books were downloaded, but it isn't enough to keep me in the program. What am I missing by not having my book available for Nook or iTunes? With my second book coming out in August, I think this is the perfect time to branch out. Who knows what my results will be, but I don't want to be stuck solely on Amazon. If Amazon decided to change the rules, and get rid of the exclusivity clause, I would likely enroll in KU once again. Things are constantly changing in the publishing world, so there is bound to be something new and exciting to try in the future.
When I started this writing adventure, I had no idea all the other things it would entail. I am constantly learning, and trying to evolve with this ever-changing market. I'm just trying to keep up!