My husband and I use different ones and we're really undecided as to which of us is getting the better deal. He has score watch for Equifax here. Generally it works fine but there are delays in how long it takes the score to update if it isn't one of the changes that are actually tracked. He also has a free account at creditkarma which isn't a real fico but is a good idea of what's going on with his transunion credit report. Usually that updates a couple days before he gets a score watch alert.
I have a USAA checking account and use their monitoring service. It doesn't provide a real fico, but I still think it's decent for tracking change over time. You can also pull all three credit reports every day for changes. I pull mine everyday just to keep track of what accounts are updating correctly and to watch for any more zombie debt to crop up.
I did buy my fico reports and scores here when I first got started a month or so ago and then I pulled them again recently to reward myself for cleaning up my credit report. It was nice to see the results of hard work. I don't plan to buy my real fico score again for probably at least 6 months as I don't plan on applying for anything until then. I may even wait until all my accounts hit 1 year old before checking the score again.
It really depends on your situation. If your only credit issue is utilization, than score watch may be the better product for you especially if your planning a large purchase in the next year or so. That way you can tweak exactly what balances on your cards work out to the highest score for you. If you've had some credit issues in the past where you could easily have a new collection from your past pop up to haunt you, then something you can check daily without the score may work out better.
My issues have everything to do with the potential for very negative surprises, so, USAA works better for me. My husband only has to worry about how his balances and utilization affect his score, so score watch works better for him.
Bang for the buck? It's probably a toss-up between TC and USAA.
It really comes down to your needs, what's being tracked, and frequency of monitoring needed. EQ has a really good daily puller, USAA has one too.
SW is a real FICO but updates irregularly. Someone needing an accurate score, tracking disputes, waiting for things to fall off, or expecting a lot of movement will just find it frustrating. People with more stable credit, like me, find the quirks amusing at some point. 
I'm cynical and can't help but feel the "It's a true FICO score, FAKOs are useless and to be ignored" only holds water if you're buying a score that day. SW's typical performance is just too low for anyone to fully trust their score hasn't changed between updates.
Don't forget some of the free ones (like CK) can be useful in tracking when disputed items fall off but may not show a lot of information on anything 2+ years old.
Starting Score: 675