With a price gap of about 300 euros between the two (if they were fully upgraded, that is) where I live, I'd say it's hardly a fair comparison. Continuing along that line: not everybody will need full trimix capabilities, increasing the gap even more. I wouldn't say these are directly competing products, but two devices each with their own market. Where the Black with EANx firmware would a great computer for those up to the level of Deco Procedures, the Petrel only starts becoming interesting beyond that point.
Ofcourse, I've taken a look at both, but alas the price you guys pay in the US is the same price as we in Europe pay: $950 becomes €950 here, a hefty $300 difference. Even if I were to get the value added tax back (21% of the 950, you can get this returned here if you own a company), that'd still leave me with a $100 dollar difference when compared to the price it's sold for in the US. For the limited amount of TMX dives I do per year, that's just not a price I can explain to myself. With the EANx upgrade, on the other hand, the computer would cost me €370 ($490), and offer me the feature set that would support me at a price that seems reasonable for the dives I do, with the option to buy an upgrade if my trimix diving increases.
I know the Petrel is a great computer, and if I were to make different dives I'd get one in a heart beat, but don't go claiming it's the one and only go-to computer out there, because that's simply not true.