In my undergrad, we used an updated version of LC-3 (called LC-4, reasonably enough) for our intro architecture course. LC-4 came with a number of "quality of life" improvements. The simplest ones were just extra arithmetic and logical instructions; if I recall correctly, LC-3 only implemented implements an ADD instruction (as well as a variant for adding an immediate value, which meant doing multiplication required manually writing a loop. Additionally, in both ISAs, branching is done using a specialized "NZP" module, where sign result of the most recent operation (negative, zero, or positive) done by the ALU would be saved, and then branching would be done based on which conditions were expected (e.g. "branch if the last result was positive" or "branch if the last result was negative or zero" (which incidentally resulted in an instruction code identical to jumping but with one less bit available to specify the destination, as well as making the selection of the NOP binary representation easy). However, LC-4 added provided direct comparison instructions that wrote directly to the NZP module without having to write to a register, which helped avoid having to write to memory as much when doing an algorithm that requires more than just a few variables.