It is deceptively huge, as this comparison with a P1 proves:
The two black antennas are buttons, alongside the traditional three, and it apparently has a couple of neat features that haven't been seen in other Tamagotchis of the era. More information and a full translation here (with thanks to OldSchoolTama for that link).
For anyone interested, it's not very expensive (cheaper than a boxed P1, in fact), and there's still one to be found on eBay from a respectable seller (I bought mine from the same guy). Check it out!
Edited by Stu_Dee_Jay, 06 November 2010 - 05:33 AM.