Setting up an email server, which at least comes close to the gmail's quality is definitely not to be qualified as "easy" process. Going through this several times, I can assure you spending good several days and nights to investigate, choose, configure, debug, and enable useful features like greylisting.

Then again, you have to worry about redudancy. How would you feel missing an important email, due to your VPS/Dedicated server being currently ddos'ed or unreachable for other reasons.

In addition, do not forget about backing up.

So, that again is in no way "easy 1 hour" task, especially for those who are doing it first time.