My first large order of hops (1kg) was Simcoe. I've used it pretty consistently since , often in combination with citra and galaxy. I've probably used it in 15 brews and as the only hop about 5 times. I would not describe it as passionfruit. The overriding characteristic (for me) on Simcoe is a resinous pine. I also "feel" like it adds an astringency or perhaps a type of bitterness that is markedly different to other hops that I have used. Like galaxy (smooth bittering), citra (grapefruit), hallertau (for me Hallertau is the archetypal reference hop - a hops hop), cascade (passionfruit) and nelson (never got the wine overtones oft' mentioned).
I've never analysed any of these in depth. These are just casual observations to contextualise my experience for others.
Simcoe is great but I tread carefully and usually do one addition of it unless it is a single hop beer (I like stouts with simcoe strangely). Lately Galaxy does most of the heavy lifting for my bittering and Simcoe is a mid to late boil. 30g for 30 mins and others in a scatter-gun approach to hit a fruit salad aroma with IBUs hovering between 35 and 50. (At a guess). Even though Simcoe is sometimes included among them I think it is a useful counterpoint to the usual C hops.
PS I have never noticed the garlic and onion that has been mentioned by some in reference to Simcoe but it's one of the reasons I don't overdo it.
Phew! Yeah. Simcoe.....Havachat why don't ya?