Hi Miles,
A lot of this decision making will be down to taste... and I say that as a Certified Logic trainer!
I personally love Logic. It's excellent value for money right now (via the Mac App Store) and comes bundled with a huge amount of content. There are a few, small long standing bugs, as there are with most DAWs, but all-in-all it's a platform that really suits my workflow and helps me to express my creativity - and comes with some awesome instruments and effects.
Cubase used to get bad press on the Mac platform. But the last couple of versions have been very solid, by all accounts, and perform well on Mac and Windows.
If you decide to try Logic out then be prepared to learn some slightly different workflows and ways to operate. If you're open to that I think the time spent learning Logic is well worth it. The free articles here (and of course the video courses) will get you up to speed in no time. Logic is a deep program, and it just depends how far you want to go down the rabbit hole.
Cubase has plenty of advantages too... so it'd be a good idea to list what your mainly use Cubase to do (e.g. MIDI, audio editing, tracking, mixing, scoring to film, etc) and whether you use 3rd party plug-ins or not... and perhaps even the style of music you produce.
Both are excellent DAWs, IMHO... and at the end of the day if you already have Cubase, then investing in Logic won't break the bank and might give you other options for composing/arranging/mixing, etc.
Hope this helps
R