Hello,
Cubase works very well with MIDI guitar. You might want to explore Step Input in the MIDI Editor chapter of the Operation Manual. Look it up in the Index.
If you create key commands for the Quantize values, then you can fairly quickly entering passages with the end result looking fantastic. Select a Quantize value, (1/1 whole note, or 1/2 half note, etc), play a note. It appears in the score. Any note you play on your guitar (with a MIDI converter) will be entered. Set another Q value (1/8 eighth notes, etc). Play more notes.
In my experience, it’s more challenging to have the score editor interpret a recorded passage. But if you want to write short scores and know what you want them to look like, then Step Input will produce beautiful results.
There are some exciting new technologies available for MIDI guitar:
MIDI Guitar app
This is a software solution that works as good as a Roland GK pickup + converter.
http://jamorigin.com/products/midi-guitar/
An advantage of the MIDI Guitar app is that you can use it with any electric guitar. No hardware installation required, except the connection between your guitar and your audio interface.
Fishman Triple Play: a wireless solution
http://www.fishman.com/tripleplay
This is more expensive but the tracking is a bit more accurate than the MIDI Guitar app.
Both work great
If cost is an issue (It’s always an issue 
), then the MIDI Guitar app is hard to beat.
You’ll have to do some reading to see if your current computer and operating system are supported by either of these solutions.