Hi all,
I was determined to get a clean render out of mantra for this sequence, which I sort of managed to do, but the render times are just too high. I'm looking at over 5 hours per frame for something that is quite simple, as you can see from the attached screen shot.

I could get something that looked reasonable, but to stop the highlights crawling between frames I just had to turn pixel samples up high. Nothing else seemed to sort out this problem (light quality & reflection quality just didn't work). The particular point I focused on was an area on the glass, on the centre of the image at the top - there's a small rectangular reflection from one of the lights, and where this went over the inner lip of the glass there were just always fireflies. The only thing that removed them was cutting the colour limit to 4 (from 10) which dulls the image, and turning up pixel samples to 12x12, which everyone seems to think is very high.

I feel there's something I'm missing when it comes to getting a clean render. I've attached the hip file which contains the geometry and the hdr so, if anyone is able to help, just open the scene and see if you can get a better render time than I did.