The biggest problem I've had doing my podcasting career is the quality of my Skype connection. For such a well established service, it has a number of deficiences. Dropped calls, fadeouts, clicks, latency issues, etc. And yet it appears to be the cleanest shirt in the laundry. Other services promise the moon and the stars, but can't deliver. Worst part is that they rely upon you sending a connection link to get your interviewee on the call. This is often problematical. As a host, you want to be in control of the call. You don't want to be sitting around waiting for your guest to remeber to connect. With Skype, unlike all the other services, either party to a call can initiate contact.
For seven years I've looked for a solution. Finally, my good friend Joe Messina has found one. Used properly, it will reduce your Skype issues by a large percentage. It's called QOS - Quality of Service. Found on your router settings, it enables you to allocate bandwith to different apps, programs and devices, either dynamically or in a fixed priority listing. It works amazingly well. If you're using a cable company combo modem/router you probably don't have access to DOS. However, you can simply configure your modem to shut down the built-in router and then connect an after market router. I'm using a Netgear AC1900 Nighthawk. It's way faster than my cable co's router and has QOS. Thus far I'm using the dynamic QOS setting and it's working like a charm. You might also want to consider it, especially if you're having too many Skype issues.