Reading the specifics of some free email services, it's clear that they engage in data collection from your email account. For example, from one free email service "The information we collect may be combined with information obtained from other Microsoft services and other companies." also "Microsoft collects many kinds of information in order to operate effectively and provide you the best products, services and experiences we can. We collect information when you register, sign in and use our sites and services. We also may get information from other companies. We collect this information in a variety of ways, including from web forms, technologies like cookies, web logging and software on your computer or other device."
I'm guessing that they all suck, but maybe there's some that suck less than others. I don't mind so much if the send me ads based on my browsing, I just don't want it to go beyond that.
Lavabit.com is pretty tight,security-wise. Zero spam gets through,plus for a mere $16 per annum you can uprate to 'Premium',which gives all sorts of advantages plus a 2Gb standard message size. I'm VERY impressed with Lavabit. Amazed it isn't better known.
Hushmail doesn't collect info to "provide better services bla bla bla...but they have admitted they will let the feds look if they ask
I don't care too much about getting spam, though it's better not to get any. I figure if the feds want to read my email they're going to find a way to do that. I'm mostly concerned about message content being read/analyzed by corporations/criminals