I liked it pretty well over all.
It wasn't the best Stargate I've ever seen, but it was good and better than many of the things they've done recently.
The time travel plot actually makes sense, save for the disappearances, but when dealing with fictional sciences, you can't say with definite certainty for example that one thing would happen where as another thing would not.
For all we know, the reason that people were disappearing *seemingly* at random could've been caused by the changes to the timeline IF time can in "reality" only change through the expanison of a temporal shockwave. The wave would progagate, causing various changes at different moments UNTIL all of reality has shifted, in order to preserve the Law which states that energy is neither created or destroyed... blah, blah-blah, blah, blah...
You see where I'm going with this?
Not a deal-breaker here folks.
And no, this wasn't Moebius either.