I'm having a hard time starting the bike, but once it gets going, it runs fine.  takes 15-20 tries with the starter, lots of fiddling with the choke, then BAM, it starts. 

Could the plugs be bad?  How does the ignition work on these bikes? -- A distributor or a coil pack?

Any troubleshooting help would be great.

Yeap could be the Plugs.Especially if they are Champions.Pull the Plugs and see what color the Insulators are.If they are a sooty black hen they are more than likely Fouling out from a Rich Mixture.The easiest way to find out is to go to your Local Auto Parts and get a New set of NGK's,Put them in and see if it starts any better.If Not try Draining your tank and putting some better gas in.Theres a Chance that you may have gotten some Bad Gas.The Gas that the Local Gas Station here sells won't even start a Push Mower.