To the OP,
Which type of lift to buy can be better answered once you've identified what you're looking to do w/it.
Having owned 3 different types of lifts- a 4 post, a mid rise scissor lift, and now a 2 post, I can tell you there's pluses & minuses w/each.
So, the 4 post may be a better choice if you are looking to store a vehicle (I stored a classic car during the winter when I lived in NH. It let me turn a 2 car garage into a 3 car. During the 3 other seasons, it was a service lift & was great for oil changes. Doing brakes & rotating tires (probably the 2nd biggest service use next to oil & filter changes) was another story. You need a sliding bridge jack and even then you're lifting either the front or back, not both (unless you get 2 bridge jack set ups $$)!
I'll move on to the 2 post now as you didn't ask about the mid rise scissor lift.
First off, I no longer need to have any winter storage as i moved back to Scottsdale.
Knowing that my top 3 uses are oil changes, tire rotation, and brake jobs; I opted for the 2 post. This type of lift provides the easiest access to my 'top 3'.
No bridge jack like on the 4 post, so front to back tire rotations are much quicker & easier on the 2 post.
Hopefully that helps you make an educated decision between 2 or 4 post.
As far as brand goes, I've seen a lot of guys here go for brands such as Mohawk, Rotary and Bendpak.
I bought my 4 post Direct lift ProPark 7 and my 2 post Atlas BP8000 from Greg Smith Equipment.
I installed them myself, not too tough. Spent the better part of a day on the installation.
HTH,
Will