OK, now on a PC with a real keyboard instead of my #$%&* iPhone, so able to give a longer answer...
The CSS326-24G-2S+RM can only run SwitchOS, whereas the CRS326-24G-2S+RM can be setup to boot into either RouterOS or SwitchOS. When the CRS326-24G-2S+RM boots into RouterOS it has full router functionality as a router, and when booted into SwitchOS, it is just a switch. I have two CSS326-24G-2S+RM switches plus a CRS326-24G-2S+RM that operates in SwitchOS. Since the CRS326-24G-2S+RM is operating in SwitchOS, it functions exactly like the two CSS326-24G-2S+RM switches. I also have a RB260GS and a CSS106-5G-1S that both use SwitchOS. The only difference is that the RB260GS becuase it's older hardware is running SwOS version 1.16 whereas the others are running version 2.8 or 2.9.
One more note about the CRS326-24G-2S+RM when operating as a router using RouterOS. It's a fairly low powered router. If you are doing a lot with it, the router will run out of CPU capability.
In case you are wondering why I bought a CRS326-24G-2S+RM to use exclusively as a switch, I didn't. I ordered a CSS326-24G-2S+RM, and the vendor accidentally sent a CRS326-24G-2S+RM in error. When I contacted them about the error, they decided that it was not worth the effort to ship a replacement and have me ship the incorrect one back; and they told me to just keep the CRS326-24G-2S+RM.
RB750Gr3, RB750r2, CRS326-24G-2S (in SwitchOS), CSS326-24G-2S, CSS106-5G-1S, RB260GS
Not sure if I beat them in submission, or they beat me into submission