I thought the whole point of trinity was the IGP. You're certainly right that Intel is faster for general purpose computation.
that's the main thing, the APUs are attractive as long as you need something better than the Intel IGPs, but don't really need anything faster than the AMD IGP...
the OP thinks the A10 is the best choice even if you only use discrete graphics, and I disagree, now if you can find the 750K (or at least some other APU like the cheaper A8 with OC) for significantly less money FM2 is back as an interesting option for this use (with discrete graphics), apart from that I would recommend going for AM3+ or 1155, but of course the IGP may not cost a lot of money overall and it adds some flexibility, you can use the IGP for a time and upgrade to some other faster card later, but if you are building a new PC with the A10 and a discrete card, I don't know...
now going back to the Celeron and A4/A6, I can see most of the people buying this not really considering gaming, so saving the money with the Celeron probably makes sense.
So in reality I see the Trinity APU as the best choice for a really small portion of the market... someone who needs more than a HD2500, but no more than a 6670 DDR3 (for the A10), or 6450 DDR5 (for the A4), and I see some disadvantage in terms of platform (less upgrade options) and the fact that video performance is greatly influenced by the speed of the ram you are using...
Has anyone used the 5800k in dual graphics with a 6670 video card? I read when they are combined (and OC'd im assuming) they equal the performance of a 7850 (ish)
I don't see much value in using dual graphics, it's just crossfire, AFR, but with 2 GPUs with different performance... so it's even more complicated, and really, you will be exposed to all the CF software issues for overall such a "low" performance? it makes a lot of sense if you have a 7970 and want something faster... but for a single 7700 ($100) performance? I don't think so.
http://www.hardware.fr/articles/878-12/amd-a10-5800k-5700-a8-5600k-5500-apu-desktop-deuxieme.html
and OC is something that will give 15-30% at best I think, the 7850 is much faster and a better experience.