I'm an Amazon Prime member and honeslty have only used only prime instant through the app built into my Panasonic TV a few times. Loaded fast, HD image looked very good, although I did notice macroblocking in solid color backgrounds. I've had Netflix for a couple of years, and keep it to watch the occasional movie. I've tried it on my PS3, Panasonic BDT310, and my third gen Apple TV, and I think the Apple TV looks the best out of the three. It has the best interface, loads fastest, and has a more stable image with less artifacting.
FWIW, your DSL is a major bottleneck for HD streaming. I used to have AT&T DSL and I could barely stream anything, let alone in HD. It always looked like garbage. I have Charter internet now and have no problem streaming in HD...my connection speed generally varies between 18-30Mbps.
desktop + headphone Sonus faber Toy monitor|REL T Zero|Sony UDA-1|Sony MDR-Z7|Sony MDR-1000X|Audioquest NightHawk|Ultimate Ears Triple.fi 10|Sony NW-A35
ht Sony A1E 65" OLED|Monitor Audio Silver RX6, RX Centre, RX1|SVS SB-2000|Sony STR-ZA5000ES|Sony UBP-X1000ES|Sonos Connect + Peachtree Audio DAC•iT|Panamax M-5100PM
stereo Sonus faber Toy tower|REL S/5|Teac UD-501|Sony TA-A1ES|Sony SCD-777ES|Sony ST-SA50ES|Sony 43" X800D|Sony UBP-X800|Sonos Connect|Furman Elite-15 PFi