What is High Definition TV ? It is what the would is migrating to. May be fully implemented by 2006 in the USA. The following link can help answer some questions about HDTV, http://www.avsforum.com/hdtvfaq/HDTV-FAQ.htm
Basically, many stations (and more every day) broadcast HDTV, I believe all the major networks broadcast HDTV at least during prime time and probably for special events like the Olympics coming up. If you have digital cable you are probably receiving some HDTV broadcasts. You can receive HDTV by simply using an antenna, OTA (over the air). You could do a search on the internet for stations that broadcast HDTV in your area.
As far as how does the Sasem compare with the Hauppage - I don't think the Hauppage has HDTV. The Sasem I believe can do everything the Hauppage can do, well, probably more considering the HDTV. Basically I just want the tuner to be able to watch HDTV, record some programs, amd maybe convert some tapes to DVD.
The Sasem OnAir USB product you will probably not find too many reviews on it. It is new, introduced in the states early this year. They have had some software revisions to it since then and have increased its capabilities. The software from what I ubderstand was good but still needed to work out some bugs and is better now than when introduced. The only source that I know of to purchase it is at copperbox.com. May want to give them a call and ask questions on the capabilities and comparisons to similar products. I plan on doing that myself. However, I have pretty much decided that this is the TV tuner I am going to get. The one thing I have found from three separate reviews I could find that was consistent in all of them - when viewing the HDTV on a laptop with this device - simply incredible.
Below I listed the features from the copperbox site.
Sasem OnAir USB HDTV Features:
HDTV timeshifting and live pause in full resolution!
New software version 2.700Beta supports recording QAM (digital cable, unencrypted feeds).
Interface with PCs or Notebooks through USB 2.0
Support Standard ATSC HD Format
Support NTSC Analog TV with Time Shifting
S-Video‚ Composite Input
Supports Dolby Surround & SPDIF (soundcard required)
Auto Power On/Off
Easy to install (Plug & Play)
Lowest CPU resource usage to decode HD streams by using InterVideo´s innovative HD decoder
Microsoft Media Center ready (MCE 1.x ; analog TV only)
PVR timeshifting and pause live TV (analog only).
Full HDTV support of 1920 X 1080i ATSC
ACS / AAC Audio Decoding output
Real-time or Schedule Recording
Hardware MPEG2 Encoding for Analog Video Source
Composite and Stereo audio input
Playback of HD Stream files (Random access)
D-VHS HD Stream playback or realtime recording (Windows XP only)
OnAir HD Editor
Intervideo WinDVD4 software bundle