I have used hundreds of intersema sensors for atmospheric pressure and 5 - 10 atmosphere applications over the last 5 years. I use a simple resistive divider for the 5>3v3 level conversion. In the 3v3>5 direction I just directly connect.

I run the PIC at 5 volts and the Intersems 5534 at 3v3 from an LDO 3 volt regulator. From PIC to 5534 I have 2k2 with 3k3 to ground at the 5534 end for signals to the 5534 DIn, SClk and MClk. DOut, from the 5534, I just hook directly to the PIC. Yes that means a 3v3 signal into a 5 volt PIC (RC.3). It works.

The HOPE is definitely a knock off of the Intersema product. Has anyone done any side by side accuracy tests? Pricing looks slightly in favour of the HOPE unit but I'm not going to make the change unless the accuracy is at least as good as the Swiss Intersema units.

Cheers
BrianT