Depends what you want to do...
We have a robodrill with a 31i and the control is better that our other machines with OiMC. This is from an operators point of view: better text editing, file handling, proper copy/paste etc.
We don't use manual guide and program everyting off line.
We also have a siemens 810T lathe with sinumeric.
This control rocks for program creation and verification, and in my opinion, why would you want to program a lathe off line, as it is so fast and easy on the control?
Before buying the siemens we had a proper look at manual guide (on a lathe) and it was crap in comparison. Thats why we went siemens.
Also, if you get a hard drive it will need replacing after around 3 years.
Maybe better to go for a control with as much memory as possible but withour the hard drive.