There is almost no difference btween UH70110 and UH70120 except for the color and the tiny design difference on the base. If you look closer, you will find that the back of the base on the UH70120 is slightly wider.
Otherwise, they are identical. Feature 12 Amps motor, cord reel, 8 feet stretch hose, 5 level height adjustment, no brush off switch, and 13.5 inches cleaning path. For more specs, read below.

Compare Hoover UH70110 and UH70120

	Hoover UH70120 WindTunnel T-Series Rewind Plus Bagless Upright Vacuum Cleaner	Hoover UH70110 Bagless Upright
Design	Upright	Upright
Price	$129.99 at Hoover.com on August 9, 2014	$129.99 at Hoover.com on August 9, 2014
Bagged or Bagless	Bagless	Bagless
Dirt Finder	No	No
Bottom-Release Bin	Yes	Yes
Cord Length	27 ft	27 ft
Auto Cord Rewind	Yes	Yes
Amps	12 Amps	12 Amps
Motorized Brushroll	Yes	Yes
Brushroll On/Off	No no way to turn off the brush when vacuum is on	No
Edge Cleaning Brush	No	No
Height Adjustment Type	Manual, 5 Settings, adjust as needed to vacuum different types of floor	Manual, 5 Level
Washable Filter	Yes	Yes
HEPA Filtration	Yes	Yes
Headlight	No head lamp	No head lamp
Weight	16.5 lbs	16.5 lbs
Performance Check Indicator	Yes	Yes
Cyclonic Action	Dual	Dual Cyclonic Air System
WindTunnel Technology	WindTunnel	WindTunnel
Nozzle Width	13.5"	13.5"
Self-propelled	No	No
Handle	D-Shaped Handle	D-Shaped Handle
Deep Recline Handle	No	No
Hose Type	stretch hose	stretch hose
Hose Length	8'	8'
Included Tools	Air Powered Hand Tool, Crevice Tool, Dusting Brush, Upholstery Tool	Air Powered Hand Tool, Crevice Tool, Dusting Brush, Upholstery Tool
Cleaning Wand	Yes	Yes
Color	Gray and Green	Light Gold
Warranty	2 year limited warranty	2 year limited warranty
Manual	download manual	download UH 70110 manual

If you know other difference between these 2 hoover upright vacuum with retractable cord, please share below.