I have a DLink DIR-655 wireless router in the front room of my 1920's house. Wireless transmission speeds were fine when close (downstairs or in the bedroom directly above), but anywhere else in the house speeds dropped to a snails pace, especially within my 2nd floor loft room. I though about running CAT5 ethernet cable throughout the house, but it would have been difficult to hide it and created a lot of mess. The only answer was to buy a homeplug/powerline, but which one????
In the end I opted for the DLink DHP-307AV/B kit. I had been pleased with my DLink router, so I thought I may as well stay brand loyal.
First impression were that these are pretty big, but made to a good quality using decent plastics. The passthrough power connector is great because it saves me having to plug it into a power strip (advised against for all homeplugs). Straight out of the box I plugged one in next to my router and the other next to my PC within the 2nd floor loft room. They autosynced immediately and I obtained a good 99Mbits download and 99Mbits upload whilst transferring files to/from my NAS drive (located next to my router). Where I used to get 2-4Mbits from wireless N, I now have 25-50x the speed. I have since ordered a third DLink powerline to install in my kids bedroon. They have also been using it happily for their PS3.
It seems that although these (and other) homeplugs quote 200Mbits max speed, they are limited by the 100Mbits physical ethernet port installed within them. 100Mbits is the most you can achieve from any such device which does not list a Gigabit Ethernet port as standard.
Overall, I am very very pleased with these devices.