I’m looking at buying an aerial tester and there are a few so which should I choose?

Digital Satellite Installation Meter with USB Interface – HDSM-USB
Enables the user to quickly and accurately perform satellite installations saving you time, money and reducing expensive callbacks. Up to 64 satellite selections can be stored by creating your own preferred list directly from the Horizon web site. Up to date downloads from the web site ensure that your meter has the latest settings and you can request custom files for VSAT installations.
Full Speed USB2.0 interface with the automatic driver download
Full backwards compatibility with existing HDSM downloads
Nylon F connectors for maximum durability
Fast processor with a recall of last selection used
L-Band, C-Band, Ku-Band and Ka-Band capability
Frequency range 950 to 2150MHz
LNB Pass/Fail test function
LNB short circuit protection
Satellite cable integrity test
Upgradeable firmware
Free product support via phone and email
Input dynamic range -65 dBm ~ -25dBm
Includes: mains charger cable, in-car charger and USB lead for data transfer
Pro+ TV & Satellite Signal Meter with LNB Power – PRO+ SIGNAL
Incorporating LNB power
Ultra-clear and sensitive
30cm Patch cable with push-fit F-adaptor
Designed in the UK for professional installers
3-Year manufacturer’s warranty
DVB-T Digital TV Signal Strength Meter / Finder – 27867R
DVB-T signal meter helps you align your aerial for the best digital reception
LEDs indicate signal strength
Connects directly to your aerial, cable or wall plate
The frequency range of 40-862MHz
Input level 50-90dBµV
Power 5VDC, 40mA
External power source 5-12V DC
Requires 9V PP3 battery (not supplied)
 DIGITAL SIGNAL FINDER

Enables the user to detect and tune in to the best digital signal available via a direct connection to the aerial using the fixing kit provided. LED display provides direction for the best possible signal.