Overall, the IDW Sonic comics have their merits. The character development and plotlines can be engaging, but it might not be everyone's cup of tea. The art style varies from issue to issue, which can also influence your enjoyment.
It's hard to give an exact number. The number of IDW Sonic comics keeps changing as new issues are released. You could look up recent comic listings or ask on comic enthusiast communities for the latest count.
The Sonic IDW comics are indeed canon. They build upon the existing Sonic lore and expand the story in new and interesting ways. Although they may have some creative interpretations, they are accepted as part of the official Sonic continuity.
In general, the IDW and Archie Sonic comics are separate entities. They have different character developments and plotlines. There might be some shared elements, but they don't have a direct connection that ties them closely together.
Some libraries also stock Sonic IDW comics. You could visit your local library and see if they have them. Another option is to look for digital comic platforms that specialize in indie comics.