Here are some of the BISSELL Revolution Hydrosteam models on the market:

BISSELL Revolution HydroSteam Carpet Cleaner, 3428
Exclusive to Walmart.

BISSELL Revolution HydroSteam Pet Carpet Cleaner 3424
Sold at Target, Kohl’s, BestBuy, etc.

BISSELL Revolution HydroSteam Pet Carpet Cleaner 34242
Sold at Lowe’s.

BISSELL Revolution HydroSteam Pet Carpet Cleaner 3432
Sold at Amazon.

BISSELL Revolution HydroSteam Pet Exclusive Bundle 34249
Exclusive on Bissell.com

The only difference between Bissell 3428 Revolution HydroSteam Carpet Cleaner and 3432,3424,34242 Revolution HydroSteam Pet Carpet Cleaner is that the 3432,3424,34242 come with one more tool – 6-inch Tough Stain Tool which is useful for scrubbing and suction away tough pet stains on carpet & upholstery. The 3428 is exclusive to Walmart, it does not include this tool.
The Pet Bundle 34249 which is only available on bissell.com comes with two more tools:
a 3-in-1 Stair Tool which is designed mainly for cleaning stairs,
and a Rinse & Storage Tray that helps you wash and rinse the brush rolls and for storing the machine and tools.

Other accessories they come with:

2-in-1 Pet Hair Upholstery Tool to clean both wet & dry messes.
8-Foot Hose help you clean hard to reach areas.
8 oz BISSELL PET PRO OXY Urine Eliminator Formula that tackles all pet messes.
8 oz BISSELL Simply Carpet Deep Clean Formula which help remove tough pet stains with plant-based cleaning ingredients.
A tool bag.

Similarities:

• Feature HydroSteam® Technology.
  “HydroSteam® Technology is a unique heater and fluid delivery system that combines steam vapor , water , and a powerful cleaning solution – working in perfect harmony to clean even the most stubborn messes.”
• Steam only flows through foot of the machine, not through the tool.
• They have water heater.
• Fingertip Power Control and Mode Control.
• 3 Modes:
  Steam Pretreat Mode to loosen tough stains before cleaning with SteamWash Max Clean mode;
  SteamWash Max Clean use water, formula and steam to clean your carpet, carpets will dry in about 8 hours using this mode;
  Quick Dry Mode use water and formula for a quick clean, carpets will dry in about 30 minutes.
• One Piece EZ Clean Brush Roll Cover is
  removable for cleanup after using.
• Have EdgeSweep® Brushes to help clean edges.
• Dual DirtLifter® PowerBrushes – 12 rows of bristles to remove embedded dirt & stains.
• LED Display to illuminates modes for easy, guided cleaning.
• 25-foot power cord.
• Separate Clean Water Tank and Dirty Water Tank.
• 1-gallon tank capacity.

You can download and read manual for more details about the Bissell Revolution HydroSteam Carpet Cleaners:
https://bissellcdn.blob.core.windows.net/cdn-storage-container/Web%20Portal%20User%20Guides/US/3432.pdf