Rabid vs Viper
Fractals and Pve
If anything the question should be Sinister vs Viper, and the answer is Viper.
https://forum-en.gw2archive.eu/forum/game/gw2/Sinister-vs-Viper
Viper is awesome, but if you want an ascended item don’t waste your time crafting one, just build a pre-HoT item and transform it in the Mystic Forge to Viper.
Viper > Sinister > Rampager and Rabid
The actual difference change a lot depending if your build rely more on condition damage, or is more balance between condition and direct damage.
Just for some quick exemple. If your build is about 50/50 between direct damage and condition. Then Rampager will be about 5-10% better than Rabid, Sinister will be 10-15% better than Rabid and a mix of Viper/Sinister will be 30-40% better than rabid.
On a build that is more 25% direct damage, 75% condition damage. Then Rabid will be better than rampager by around 5-10%. But Sinister will then better than rabid by around 20% and a mix of Viper/Sinister will be better by 40-50%.