I have to contribute my experience here.
On Monday I took an Apollo on trial basis for that same reason of No latency monitoring. That aspect in itself works well. However!, I was horrified at the latency figures with the Apollo. Way higher than my current MR816CSX.
At 88.2 Khz and 128 Buffer
MR816 - IN 2.540 / OUT 1.814
Apollo - IN 7.937 / OUT 3.685
At 88.2 Khz and 32 Buffer
MR816 - IN 1.451 / OUT 0.726
Apollo - IN 6.848 / OUT 2.596
Although as you can imagine running at 32 buffers really chokes most systems.
Now these are still low but when you are trigger an E drum kit and VSTi superior drummer you notice that delay difference, just.
In my opinion, although I will end up buying an Apollo however, the time to buy one isn’t there yet as they have not provided the quality low latency drivers that are needed for todays VSTi’s. Not to mention the fact that they are ripping people off with their bundled plugins. A device costing this much ought to come with so much more included in that respect.