Check out the Server Status Page!

Oh lol. Well, time for some comparison:

Southperry/MMOStatus:

+ Original
+ Clean interface
+ Support for multiple games (MMOStatus)
+ Shows Cash Shop and MTS Status
+ Shows server latency
+ Can see all servers with one glance
+ Works even if Nexon.net is down

- No own status for "Recently Restarted" or "Maintenance"

Nexon Server Status:

+ Pretty Interface
+ "Recently Restarted" or "Maintenance" statuses
+ Slightly faster updating (assuming Nexon has automated it)

- Not original idea
- Supports only MS servers
- Doesn't show Cash Shop and MTS Status
- Doesn't show server latency
- Too many spoilers
- Not available if Nexon.net servers are down