The Nillkin one cost $9.99 (£6.09) with free shipping from
Obostore - Delivery took almost 2 weeks. Not bad for air mail + free postage!
Material/Feel
Both cases feel exactly the same, they're matte and rubbery but not overly rubbery like some cases and no slippery rubbery either. They're just right. They're about the same thickness as well so keep the Galaxy S II's slimness when attached.
Protection
The Samsung one offers side protection from knocks and falls but no top or bottom protection, the corners are mostly protected but not completely so falling at an odd angle could cause corner damage to the handset, even though I don't know of anyone who has had that happen (yet) some people might find this a concern.
The Nillkin one protects the corners completely and because of this falling at a funny angle won't cause any corner damage unless it falls top or bottom first into the edge of an axe (quite unlikely I think you will agree
).
The camera lens cover has an extra edge of protection on the Samsung case as it's recessed in AND has a lip where as on the Nillkin it's only recessed in a bit. you won't scratch the lens when laid flat on a surface on either case though.
The screen protection is slightly better on the Nillkin as the lip is slightly bigger than on the Samsung case so you have more of a gap between a surface and the screen when it is placed face down.
Design
The Samsung cuts around the holes of the phone, like the headphone/charger ports whereas the Nillkin does not, this isn't a big deal really but it's a difference so I guess it's worth mentioning anyway.
The Nillkin case fits tighter than the Samsung one. Someone on XDA said their Samsung case flew off when their handset fell once, quite unlucky because mine fell once too on laminate flooring and it didn't fly off but there you go, it happens. I don't think the Nillkin will be flying off given how it fits around the phone.
The Nillkin feels a bit slimmer than the Samsung even though they're the same thickness. I realised this was because the Samsung one curves less around the phone and has a slightly more rectangulatr shap around the edges of the phone whereas the Nillkin curves with the phone more giving the illusion of a slimmer case.
The Samsung case
will collect dust between the holes and this dust will settle on the back of the phone, you will see nice polka dots when you detach the case on the battery cover and lower part of the back, it looks weird o.0 but it's easy enough to blow/wipe off.
The Nillkin comes with a screen protector which is rubbish and a little cloth.
I've decided to keep the Nillkin on due to the above plus points. It doesn't look as cool as the Samsung case but it offers better protection and feels a bit better in the hand too. Oh and it's a few quid cheaper.