The P238 had a rough start when it was released (having just recently moved up to an overall reliable status), however, it wasn't a SIG SAUER design; it was a remake of the Colt Mustang. The P290 is a new SIG design, and I think it will have a start that more closely resembles the quality that we expect from SIG. The size is almost identical to any P238, and the weight is that of the P238 HD. So if you've every handled the P238 HD, you should know exactly what to expect carry-wise.
I am looking forward to this micro-compact very eagerly. I will definitely not be the first to buy it; but a year or so after its release (as long as the range reports are favorable), this will replace the .380 ACP micro-compact that I plan to buy in the next few months. I am not impressed with any of the micro 9mm Para models that are currently out (either because of quality, size, or price), but I think this will change my mind (and I'm sure that other manufactures will follow in the footsteps of this gun).
I haven't seen SIG SAUER say anything official on the matter of price (it definitely doesn't say anything about it on their website), but there are several places that have said $530 will be the MSRP. If that's true, it will be cheaper to pick up this model than a P238.