I assume you are refering to the XE 840, which is the only dual core XE out. There have been previous XE processors which you could probably compare to an AMD FX processor, the XEs originally featured bigger L3 caches of 2MB, but that is nothing special now.
I wouldn't say it sucks as it is a high end processor and I would kill have one handed to me for free, but compared to the Athlon X2 processors, it is quite a disappointment.
Intel C2D E6320 / AMD Athlon X2 3800+
Gigabyte 965P DS3 / DFI nF4 Ultra-D
2GB OCZ Gold PC2-6400 / 2GB OCZ Gold PC4000
eVGA 8800GTS 320MB / eVGA 6800GS 256MB
150GB Raptor / 74GB Raptor
2x500GB / 320GB
OCZ GameXStreme 850w / OCZ StealthXStream 600w