The Rami BD and the SIG 938 are both great guns...sub-compact vs. sub-sub compact, the 938 is obviously a lot more concealable and easier to carry, the Rami gives you twice the firepower in a sub compact, but is still a bit of a chunk to carry.
Both have been reliable and accurate for me, bear in mind, though, that SIG has had a lot of quality control issues over the last few years. The 938 had several bugs initially, but I believe they have been sorted out in new production guns. The most disturbing is that the 938's recoil spring guide rod assembly has been known to unscrew itself and separate during shooting (flinging the rod out the front of the pistol), so that's something to watch.
Since SIG churns out about 500,000 guns a year, quality can be hit or miss compared to CZ. You read on the SIG forums that it's not uncommon to have to send new 938s back to the factory for tweeking or total replacement.