Using an 8051-based trainer like this is definitely a retro choice even just in terms of 8-bit solutions. For example, Atmel has had AVRs that are pin-compatibl

Using an 8051-based trainer like this is definitely a retro choice even just in terms of 8-bit solutions. For example, Atmel has had AVRs that are pin-compatible with their 8051 line ever since they introduced the AVR and it's just so much nicer in terms of instruction set, peripherals, etc. Normally you'd use an external programmer and development toolchain these days too.