Unfortunately the server population has gone down from what I have noticed. When I originally started playing I recall playing on S3 which now has become something of a memory.
As for the house upgrades there a few things they offer:
- Rebel clothing store (5 million)
- CCTV (5 mill~)
- House level 1-5 (offer 20% increase of inventory space and time taken to get into the house price increases quite heavily after each upgrade)
- ATM
- Spawn point
That's about it. Can access with windows menu when inside the house.