Well it depends on your knowledge and skill and what your Printer is happy with.
I'm pretty experienced and expert at making the most unlikely software do stuff it wasn't intended for and I'd be very hesitant at using Pages for anything beyond fairly straight forward layouts. Straight forward layouts being clean cut vector text, shapes and lines without 3D charts, fancy borders, bitmap transparency, shadows, reflections etc.
If you are prepared to put a lot of manual checking and some initial planning and testing into the job you may survive reasonably intact.
What were you using on the PC? The only software I can think of in a reasonable price range but with semi-Pro features is Serif Software's line of DTP software. Personally I never bothered with it, but on paper it looks acceptable.
If you want bleeds, crop marks and some basic imposition on the Mac without breaking the bank, Swift Publisher will do those but still has issues with color management and lacks a range of Pages' better features.
Quark XPress and Adobe Indesign really are THE tools for Pro DTP no matter what platform you are on.
Peter
PS Click on my blue name and email me a sample pdf of your previous newsletters and I'll let you know if it will work in Pages and if not what the issues are and what to avoid.