Seems like I'm having the same issues - sounds great in Cubase, then seems quiet and lacking in dynamics in the mixdown. It's like being a drowning man seeing the shoreline just out of reach. I thought I'd done all the hard work in the recording. Just want the mixdown to sound like it does in Cubase - how simple is that?!
Tried one suggestion, reduced the main mixer stereo out channels to below 0db. I had a couple of 'hot' tracks, namely the drums. I don't know if I did the next part right but I 'Normalised' all the tracks to 0db in the 'Audio Processes' to try and make the sound a little louder and more vibrant as it does in Cubase - still no joy.
Guess I'll have to try and understand the theory behind using compressors and limiters - had a look in the Cubase inserts to see if there were any tools in there and couldn't find any.
It's a bummer being a newbie