At one time I have messed with all 3 mentioned and some that haven't been (Xara Xtreme being a fav of mine (on Linux)).
I still have a copy of DRAW X6 that interfaces with my digitizing program, never really bother to install it. My experience stopped with X5 (not trying to say that it's a bad program, just mentioning what I do). Unless you are able to find, install and run Corel 9, you aren't going to be able to get it to run "natively" on the Mac.
That leaves 2 that were mentioned.
Inkscape is free period and Adobe should still have a 30 day trial, but I don't use their CC programs, so I don't know if that still applies to them or not.
As much as I like and advocate FOSS, I go with is more efficient for my business.
Inkscape is a decent program, that may be more then enough for your needs, but I have known it to be more powerful then Ai/DRAW in some respects, but then really being lacking in others. That's my experience, other's mileage may vary.
There are times when I'll run Inkscape on the Linux side, but more often then not, I'm opening up that VM of Windows and I'm running Ai. I should mention that 98% of all outside files that I get are raster based, so that wouldn't present a problem with getting customer files for me and what program I use to open them. The majority of vector files that I deal with are ones that I create and I'm still going to Ai. But then again, you have to remember that I cut my teeth on Ai, so having learned on it first, there is some familiarity to it.
If you do accept outside files and get a lot of vector files, Inkscape may be able to read them, but there is quite a lot of lost info as well. The biggest one for me is layer hierarchy and that could be a problem with tweaking the design if you have to. How Inkscape handles layers in general (although it did get better with .91) is a big turn off for me as I use a lot of layers.
They are all going to have a learning curve though. They all have their pros and cons.
Edit: I see rjssigns snuck in another suggestion, while I was typing the above. I've heard good reviews of it, no experience with that one though. When it was first out, I had already converted the one Mac that we had that I would use to just Linux. Alicia won't let me do anything to her Mac (yet).
