Will it run GSPro well?

XOTIC PC states both processor options are fast enough to work with golf simulator software like GSPro. The better fit depends on how you use the machine beyond the simulator.

Which processor option should I pick?

XOTIC PC frames the choice around your use case, since both are described as fast enough for simulator software. Pick the higher option if the PC will also handle demanding games or heavier multitasking.

Is this a full simulator package?

It is a desktop PC package. A launch monitor, hitting screen, mat and projector are separate parts of a simulator setup and are not part of this desktop.

Can I use it for regular gaming and work?

It is a desktop PC, so it can run other games and everyday software. The build is positioned around golf simulator performance, so check the full configuration for the rest of your needs.

Is it worth it over building my own PC?

You pay for a configured, ready-to-run machine aimed at simulator software. Building yourself can cost less but requires matching parts and setup work.