As an owner of a Speed3, I can tell you that they are a blast to drive. I've had mine since May of 2013 and it has about 32K miles on it. I change my oil (synthetic only) every 4-5K, just depends on how hard I've been on it, ambient air temps, etc. I've not had any issues with mine other than uneven tire wear, which is a well-documented problem with the Speed3s on the Mazda forums. (Gotta have camber plates) Mazda messes with the alignment pretty aggressively to help compensate for the torque steer. Personally, I've never had an issue controlling the car but apparently people who don't know how to drive end up putting them in ditches.
I can not speak as to the reliability / drivability of the older Speed3s, as mine is the only one I have driven.
We used to own a G35 coupe that was a blast to drive. A 6MT G Sedan is on my short list.
