Alright, they make some bad-mothuh-truckin' espresso drinks, so I am definitely a fan.
For Vegas, the prices are pretty legit (i.e. $4.75 for a large blended drink, $4.00 for a medium latte, etc. etc.)
There is a Starbucks right around the corner--well, around the corner and down some way--but I would take the time to head to Espumoso just because the cost is about the same, but the drinks really do taste better.
The service is lacking a little bit, but what can you expect? It's the Hard Rock Hotel and all of those kids working there have some kind of attitude (unless you're in the HRH tower, then you're golden)
Go forth my dear reader, and enjoy some coffee made with a REAL espresso machine.