Gizmo is more well-suited for my particular needs as a highly mobile laptop user and in most regards, I thought it was more straightforward than Skype (with Skype I always feel like I'm having to proselytise disciples for them; not so with GizmoCall.) However, as you'll see from the above-mentioned & at least one tech blog (check the "Grand Central" link in the Google results you'll get), it isn't without some Day 2 blues
Once those small speed bumps are smoothed over, easy breezy!