When researching portable blue-ray players the features that I am most interested in are the size of the unit and how portable it is. The size and quality of the display. Battery life is another important aspect for a portable unit. They all seem to come with AC,car chargers and a rechargeable battery The main feature that seems to vary between units are the input and output options. I believe you want to at least have HDMI out so you can use the unit for your home theater. Inputs might not be as important but I believe this is a feature that should be included. Online connectability is another feature that seems important so you can stream netflix or other internet tv features.
Samsung BD-C8000
The Samsung BD-C8000 is a 3D portable Blu-ray player with internet TV and wireless built in. 1 GB internal storage. A 10.3″ 1080P LCD screen, at 1024×600. HDMI out but no AV inputs. Plays 3D but display is not a 3D television. Slip cover carrying case. Includes splitter for second headphone. Buy Now
Panasonic DMP-B100
The Panasonic DMP-B100 Blu-ray player has an 8.9 inch LCD screen. The unit weighs 3.1 pounds. Built in 2 channel speaker. Comes with AC power supply, DC (car power) adapter, and 3.5 hour rechargeable battery. 1024 x 600 resolution. 1 year warranty. Dolby digital sound. One head phone port. No internet TV and no video outputs. Buy Now
Philips PB9001/37
The Philips PB9001/37 Portable Blu-ray player offers 1080P high definition resolution on a 9″ screen with TrueHD Dolby Digital. The unit weighs 5 pounts. Compatability in multiple formats including MKV, DivX, MPEG, WMV, VC-1, and H.264 with a USB port. DVD upscaling for an amazing picture. One year warranty. Includes remote, AC power supply, DC car adapter, AV cable and travel pouch. HDMI outputs. Two headphone ports. 3 Hours on Battery. Buy Now
Sony BDP-SX1000
The Sony BDP-SX1000 Blu Ray Disc Player comes with on unit touch controls. With industry leading 5 hour battery life. 180 degree swivel flip wide 10.1″ LCD screen. Product weighs 6.1 pounds. USB port and HDMI out. Screen resolution 1024×600. Buy Now
Somethings to think about when buying a portable blu-ray player is size and resolution of screen. The next important element in my opinion is battery life. Is one movie between charges enough? Do you want to be able to use the device on your home theater? Will you want this to be a backup unit and if so it needs a digit output such as HDMI. Is internet tv important? Will you want to stream multimedia off the internet such as Netflix or Youtube. As an amateur film maker I would want a unit that I could play back my own videos through an external storage device so it needs to have both an input and the ability to play multiple formats. Not all units offer these features so you need to figure out which features are important and base your purchase accordingly.