The good thing about Gmail is the excellent spam filter and the fact that it is likely to be around for years to come.
Although I am also concerned about privacy, Gmail is certainly a good service. Probably the best on the market.
I have heard about a trick where a person could use an alternative email provider but somehow route emails through Gmail servers to take advantage of their Spam filters. I am not sure of the details of this, but maybe it is a way of using Google services without compromising privacy ??
Gmail is very good for a lot of reasons but also very un-private. Agreed - their spam filter is one of the best. The 'trick' for alternate email is to route your other email through POP/IMAP under the Send/Recieve As feature.
One reason I like Fastmail for my 'general' email is their incredibly advanced spam/virus filtration. It's on par with Gmail in most cases and offers the privacy of a paid service. If you have Fastmail on a legacy account plan you should NEVER let that plan expire, it's only $9.99 a year! I plan to never let my general, non-secured Fastmail account expire from the legacy plans as the current plans are expensive in comparison.
Posteo is good, I used it for awhile. My only complaint was their spam protection is too good sometimes and doesn't offer granular control. They simply reject high-probability spam outright without any notification to you. Not a problem for most people, I am just anal at seeing ALL of my spam! Fastmail has been caught doing this as well, which is why I rely on Fastmail for my general box and not important things.
Fastmail and Posteo are my two favorites for 'general' stuff.