They are owned by the same conglomerate that owns Omega. They both use ETA movements, so you're correct. I believe Omega modifies some of the ETA movements, but still its a great movement and Tissot are indeed nice watches.I have to agree about Sekondas, the are solid and reliable watches that really look the part.
Though I have to admit I've recently taken a fancy to Tissot watches. I got a PRS 200 on my honeymoon tax free and it's an amazing watch. The build quality is up there with the best of them and rumour has it that they use the same mechanisms as their more expensive sibling Omega.