Knowing what we now know, I would definitely not get the Sig Model S again.
But that said, if I wanted an SUV vehicle, I'd probably spring for the Sig X. All my gripes with the Sig S stemmed from the fact that Tesla was clearly learning on the fly and incredibly unprepared for a rollout of 20k per year production and delivery schedule. However, I think most of those issues have since been resolved and the systems are now in place (and Tesla has the street cred with suppliers) to prevent a repeat disaster scenario with the Sig Xs - and I don't think it's unfair to describe the Signature S debacle as a disaster as the company clearly missed its own financial and timeframe guidance multiple times and it likely contributed to the need for a secondary stock offering.
Here are the reasons why in retrospect I think the Signature S was more hassle than it was worth: our car was extremely late, calling the communication poor would be overly generous (3 delivery windows missed with no one calling to tell us that we had cancelled our vacations but wouldn't be receiving a car that week anyway), and when it did arrive, our car had a very long due bill list. We seriously considered pulling our deposit up until 2 days before the car ultimately arrived (if your car's delivery was more than 60 days late, early sigs had the option to get a full refund).
The reasons for these shortcomings have been well documented: 1) suppliers didn't think Tesla would ramp up as fast as it did, and parts (especially carbon fiber ones) held up production, 2) we were switched between 3 different delivery specialists throughout the process, and they didn't have the computer systems in place to really switch off. Hence we had to resubmit the same paperwork many times to many different parties as Tesla continued to build its staff up on the East coast; and 3) general poor planning in underestimating problems that would crop up and have credible back-up plans to keep customer frustration at a minimum.
We were always willing to pay a little extra for no real benefit but a few months earlier delivery. Paying extra, cancelling trips for nothing, and generally stressing out for all of fall '12 about whether we'd ever even get a car though was not part of the original calculus.
For the most part I think these issues have been resolved. I think the roll-outs of the Sig X's will be much smoother, and if it's not then the signature offering should definitely be discontinued for all future products.