300mm vs. 400mm

I already have a 100-400. Looking for a prime (that wont break my back or bank) on the long end. Like to shoot birds, flowers, insects, etc.

300mm IS + 1.4 TC will do you very fine.

Yeah, if you want to do both I'd suggest the 300mm f/4L IS; the 400mm f/5.6 doesn't focus close enough to work as a good macro lens.

If its birds your after, the 400 F/5.6L cannot be beat. Everything else, the 300 will be just fine

the 300 is awesome, you'll find the close focus very nice