The ATI HD 5450 and Sapphire HD 5450 are very similar. Both use passive coolers and both are low profile. What's interesting about the reference ATI one is the fact the cooler is a dual slot one. Considering the market, this is a bit disappointing; it's clear that Sapphire saw this and for that reason opted for a single slot design.
Connectivity is the same as the Sapphire one which is no surprise. From the left we've got a VGA port, DisplayPort and Dual-Link DVI connector. You can run Eyefinity with this model, but you'll have to have one monitor hooked up via VGA which is an analogue connection instead of digital like the other two ports.