I have both a 4 post lift and a scissor lift, in different garage bays. 4 post for storage, scissor lift in the garage where I work on the cars. Personally I wouldn't use the 4 post for working on a car, I wouldn't find it helpful for that purpose.

 

I've also got a 4 post lift with two air powered bridge jacks. Makes it really useful for wheels off work like brakes, suspension etc. For stuff like engine/transmission out a 2 post lift is definitely better and a 2 post is arguably better for all sorts of just mechanical work. But a 2 post lift sucks for storage, wheels on work (exhaust, torqueing suspension bolts under load and ease of installation in a residential garage. Everything has its pros and cons, you just need to pick which works best for you.
If I had the space, I'd also have a 2 post lift in my garage too...