Gems of MoP..

[Silvertaurus]

With MoP the gems have new ratio of Primary to Seconday value on it.
By Blizz primary stats are worth exacly twice as much as secondary, what is not true at least for Shadow Priests.
Following by gear guides, haste is worth ~0.78 and hit ~0.61 of primary stat INT.

Does it mean, we rather skip INT if its possible while gemming ?
Taking pure SPIRIT into blue, pure HASTE into yellows, and for red we go hybrid INT/HASTE ?
Maybe even skipping red slot bonus (if its poor) by going pure HASTE gem?

[aica]

Probably until you hit 8085 rating, anyway.

[Schisme]

With MoP the gems have new ratio of Primary to Seconday value on it.
By Blizz primary stats are worth exacly twice as much as secondary, what is not true at least for Shadow Priests.
Following by gear guides, haste is worth ~0.78 and hit ~0.61 of primary stat INT.

Does it mean, we rather skip INT if its possible while gemming ?
Taking pure SPIRIT into blue, pure HASTE into yellows, and for red we go hybrid INT/HASTE ?
Maybe even skipping red slot bonus (if its poor) by going pure HASTE gem?

Yes, however you'll want to use Haste/Spirit in the blue slots. That's assuming that the socket bonus is worth it. You'll want Haste/Spirit because you'll likely be transferring crit or mastery to hit/spirit to hit the cap which means you're getting more haste, the better stat.

Also, the 2nd poster was correct. This dramatically changes once you hit the 8085 haste breakpoint.

[Nephelee]

If you can't hit 8085 haste, even with gemming haste, wouldn't that devalue it a bit?