SIDs do have a tendency to get pretty warm (you should at all times be able to keep your finger on it). If it gets hotter than that there's possibly sth wrong. Check the wiring, voltages, ... If that doesn't bring solve it - add a heatsink.
Solidworks is not over the top, but a really bad choice. If you're not already really really good at laying out PCBs you should really really go with a pcb design app, as they do a lot of the work for you. Like error checking and the likes ;)
For me it's: * The UI actually got worse. It runs a lot slower than 4.x on pretty much any Windows machine I tried it on (supposedly this is not the case on MacOS) * The new drawing algorithm limits the selection of useful colors even further as most color combinations just lead to an unreadable mess. * A lot of commands have been moved into popup menus that were not there on 4.x, which means a lot of extra mouse moving and clicking. That doesn't really sound all that bad, but it's incredibly annoying when you're tweaking a layout and spend 30% of the time clicking menu items that weren't necessary or even there at all before.