I purchased this bumper to try out on my S5: http://www.ebay.com/itm/191134013378...84.m1439.l2649
It finally arrived today. The design is slightly different than shown in the pictures and different than other bumpers i have had (note 2, for example) in that it's a single piece of aluminum with a clasp at one corner. Looking at and feeling the clasp, it's a solid connection and the bumper fits perfectly on the phone. I suspect the clasp may fracture if you dropped the phone on concrete, but the bumper would probably stay on.
Button clicky-ness is well retained, port access is great, the giant LOVE MEI logo is atrocious and i'll be sanding it off promptly.
Signal strength does not appear to be impacted. I haven't done empirical tests but i did walk around the house a bit and speed tests on wifi do not indicate any impact.
I don't have a wireless charging back yet, but given the design of the bumper i'm hopeful that it will still work with the Qi back. We shall see. On to pictures...
20140502_142820 by Mechatricity, on Flickr20140502_143017 by Mechatricity, on Flickr20140502_143557_LLS by Mechatricity, on Flickr20140502_143230_LLS by Mechatricity, on Flickr20140502_143256_LLS by Mechatricity, on Flickr20140502_143238_LLS by Mechatricity, on Flickr20140502_143410_LLS by Mechatricity, on Flickr20140502_143424_LLS by Mechatricity, on Flickr