The VM is great for learning the command line. However there are some things that the VM lacks in... just the physical, how to do things, the process of upgrading a switch for a beginner, having the serial port, dealing with the boot rom, all good things for a learner to have hands on equipment.
to answer the OP, Find x440 x460 if you can , older x450s are a dime a dozen right now, but they are limited in software.( r 12 I think?) .. and of course stay away from any 200, 300 400 models ( they run EWARE not xos) stick with the 440/450/460 models. when you get to learning PIM and OSPF there is a trial license to enable the higher license of a 460 for some of those commands ( it is time limited and can only