Ditto on SGP. I bought Zagg from Amazon. But it's just God-awful. Replaced the front with SGP Oleophobic and back with EX Ultra Crystal (both purchased from eBay). Will replace the back with one of the matte films when available (either EX Ultra Fine dry application or Ultra Matte wet application).
Quality comparison between the two brands will be just ridiculous. SGP is superior in every aspect: feel, look, installation, packaging... Plus, you get a lot more choice of film types: matte, clear, oil resistant, dry/wet application and so on. Reviews/photographs are available here. Just search for the brand/type that you're interested in.
In terms of quality, I'm told Power Support matches SGP products. But it's not available here in the UK. Not yet, anyway.
Do not bother with ANY of the unknown brands sold in High Street stores.