The SSD gives a big performance boost. Unless you have little data or a big wallet, replacing the hard drive with a SSD drive is not ideal. The combination of SSD for System and Application files and a hard drive for the rest works great.
You can read more about this 2011 model at Mac mini "Core i5" 2.3 (Mid-2011) Specs (Mid-2011, MC815LL/A, Macmini5,1, A1347, 2442) @ EveryMac.com
. In addition to the SSD, the memory is upgraded to 4GB.
Asking $550. I would prefer a local sale in Ottawa, but will consider shipping at buyer's expense.