Typically the purpose of a chip breaker is to force smaller chips instead of strings so a heavier cut can be made at the expense of lower quality cut. Thus you can rough cut faster with higher DOC and feed rate but then you'll do a finish pass with a normal bit and overall saving time. But you'll have to do a tool change and your finish bit will last longer and so does the roughing bit.
You can also just use a standard solid flute end mill, which will need to cut a little slower than a chip breaker, and avoid the tool change steps as a previous poster mentioned. However, I found that once calculating the feed/speeds based on the ideal chip loading for most end mills, the Axiom generally won't quite go as fast as possible for some of the tool setups - especially for woods. In other words, I don't see a need to go with a chip breaker in most cases.
A good fresh/sharp upcut end mill leaves a razor sharp edge both sides of decent plywood but starts to frizzle when it gets dull. Use a compression bit (has both an upcut and downcut portions) if you want a super clean edge on each side and let it go a little longer as it dulls.
Next point, for plastics, a single flute end mill is advisable. Be sure to calculate feeds and speeds to get the most out of your machine, tooling, and material. A good place to start is here. Their free online tool doesn't have all of the available variables but it will get you started. zero-divide.net/?page=fswizard