I recently switched from StraightTalk to Cricket - for my wife and my phones together it's a bit cheaper ($70 total including taxes and fees), and has worked quite well for us. I was on the $45/mo ST plan before, and it also worked admirably; I switched just because of the price difference.
The one problem I had with ST: The first two numbers I got from them received seemingly *endless* calls from debt collectors/marketers/etc., for the previous owners of the phone #. I had to switch a few times until I got one that wasn't horrible. I don't know if that was just bad luck or a consequence of the brand, but know that you *can* change your number with them. This isn't an issue if you port your own number. The customer service kinda sucks, but you can get through it.
The only issue I've had with either is slightly more limited roaming. There are some spots in the middle of nowhere where there's emergency service, but I couldn't roam on Cricket or ST (some of the tiny towns outside of Yosemite, for example).
If you decide to try cricket and click this link and sign up, we each get a $25 credit:
https://refer.cricketwireless.com/5Veafgr(But if you have any friends that use Cricket already, ask them for a referral. ;-)
If you prefer the non-referral link, cricket is:
https://www.cricketwireless.com/Thus far, I'd say that Cricket & ST are equivalent in most ways but Cricket is cheaper, and they're both a way better deal than our old AT&T contract. (duh). The even cheaper options on the MMM blog, like Republic, are interesting, but my wife and I are both so cell phone (&data) reliant that we didn't explore them much.