Dramatically improved (Destiny)
like... 10 times better. Almost every game I played last night, someone got a legendary. More than half of the legendary drops I saw were IB drops. Some of them were above 300 light. Lots of the blues I saw (and got) were in the 290s.
That being said, you can't get IB legendary drops until you hit rank 2 with IB, and the pool of available drops increases as you rank higher and higher.
Complete thread:
- 320 Armor rewards confirmed in IB - 
Schedonnardus, 
2015-11-19, 12:25 
- 320 Armor rewards confirmed in IB - MacAddictXIV, 2015-11-19, 12:33
 - What about drop rates? - 
TheeChaos, 
2015-11-19, 13:20
- What about drop rates? - 
MacAddictXIV, 
2015-11-19, 13:34
- What about drop rates? - Kahzgul, 2015-11-19, 15:44
 
 - What about drop rates? - 
Schedonnardus, 
2015-11-19, 13:34
- What about drop rates? - Kahzgul, 2015-11-19, 15:44
 
 - Erm, kind of? - 
someotherguy, 
2015-11-19, 13:45
- Erm, kind of? - Durandal, 2015-11-19, 14:07
 
 - They are better - 
unoudid, 
2015-11-19, 14:10
- They are better - bluerunner, 2015-11-19, 14:48
 - I got a pair of 280s! :) 
 - 
Claude Errera, 
2015-11-19, 15:53
 - Wow, not my experience - Beorn, 2015-11-19, 19:54
 
 - Dramatically improved - Kahzgul, 2015-11-19, 15:39
 
 - What about drop rates? - 
MacAddictXIV, 
2015-11-19, 13:34