As for flywheel weight on CDI units(Treats vs. HPI)-
The treats version is real close to stock points version, close enough not to be able to tell a difference in the throttle response when you rev it. The treats version has a killer 12V light coil that can handle whatever you throw at it (electrical wattage) and then some.
The HPI has an internal flywheel, ie it spins inside all the components and is of an alloy material. Thus it is extremely light and you can tell by the response of how quick the engine revs up on a stand. The light coil for the HPI is a 12V, but has verry little wattage and can power a regular tail light but not a regular headlight (it puts out only 10W).
The first pic is of the treats CDI flywheel, not very different from a stock flywheel, the second is the HPI flywheel.
As for running better and starting better, CDI is low/no maintanance and points need to be cleaned and adjusted frequently but there is no starting difference.
What I've noticed performance wise between the two cdi's, is that the HPI had less low end torque but could get to the top quicker, rev higher and a better throttle response. The treats had more low end torque with lights and horn that were better and stronger than stock.
So, for a daily runner go with the treats version or points(stock), for a dedicated race bike go HPI.