Osteria is one of those hit or miss places. We've had awkward interactions with the staff there on more than one occasion. Once, the server didn't seem to know the menu very well and then another time a different server made it appear that we should've made a reservation, but then told us to sit anywhere we want as long as there wasn't a "reserved" sign on the table. Just a bit weird. We wound up sitting at the bar.
The food is okay for the most part. Sometimes the pasta can taste overcooked. We know it's made in house, so I'm guessing they just have "off nights"? My husband loves their mussels dish. His favorite part is sopping up all the sauce with the bread. However, I'd steer clear of the pizza. It's like eating pizza sauce and cheese on a saltine cracker. It burns very easy and it's just not good.
Their pastry chef makes all the desserts in house. I will say that their tiramisu is delicious.
One last thing is that there isn't really a comfy seat in the place. You're choices are either wooden benches, wooden bar stools, or aluminum chairs that look and feel sort of flimsy.
We are Strip residents, so we usually head over to this place once every couple of months. It's not horrible, it's an okay place to get a meal in the Strip and the prices are pretty reasonable. But, as I said before, it's hit and miss.