Keyclone is an excellent program as far as key replication goes.

It doesn't have the flexibility of IS Boxer, for Keymaps, which are highly configurable hotkey/target/action commands. IS Boxer is far stronger then Keyclone as far as mouse broadcast and PiP swaps go. If much stronger keymaps, mouse broadcasting and PiP swap speed is important, I'd consider IS Boxer as an alternative to Keyclone.

It is worth mentioning Hot Key Net. This program is free, unlike IS/IS Boxer (which is subscription based). HKN uses scripts, so its harder to tweak then Keymaps within ISB. But the program is just as flexible and has superb mouse broadcasting like IS Boxer.

If you can get by with key broadcasting alone, Keyclone will be fine. If you want the PiP swaps and mouse actions, I'd definitely move to HKN or IS Boxer.