Person of Interest is one of the best shows on television right now. It's really, really good.
There's really nothing in the show (so far) that's reminiscent of the stuff that led to the issues with Alias and Lost. The machine that provides the numbers has been completely explained, from fairly early on, and while there are flashbacks, they don't happen every week. And when they do have them, they actually help move the show forward.
Love that show. Haven't missed an episode since it started. You're really doing yourself a disservice if you don't watch it based on previous Bad Robot missteps and I would (and do) wholeheartedly recommend it to anyone with zero reservations. It's that good.