I own one more out of just curiosity, but also have S and HO scale MTH PS3 engines, so it's a way to run those tracks and layouts.
I could not recommend it for general O scale used for the following reasons:
#1 it outputs DC on the track regardless of input (in other words, you can use AC going in from a transformer, but it is rectified to DC on the output). This is problematic because there is a long list of Lionel products and cars that cannot be used with DC on the track. Basically anything using a TRIAC- they need the zero crossing of the AC waveform to turn off.
#2 The firmware is not updated and it's kind of an abandoned platform. You cannot do lashups and a number of other things
#3 Again if you do use the variable out function, it is variable DC out which a lot of Lionel stuff may not be happy with.
#4 It is current limited, and it also doesn't like voltage spikes- a couple people have damaged the output section.
Again, it's not terrible, but also not ideal. It had it's purpose and place- really around 2 rail DC smaller engines like S and HO.