CF to IDE adapters are completely passive devices. CF cards are native IDE in the first place. (They also support other modes, but that's of no consequence to us.) The adapters just give you a way to plug them in. There are no bridge chips for CF-IDE. CF-SATA would use the same bridge chip (i.e., Marvell) that early-generation SATA drives used. There is little to no performance loss with such a bridge chip.
The catch is that nearly all existing CF cards only support PIO transfers, and that is a huge bottleneck. The other problem is that Flash has always been a slow technology, but it's been gaining speed quickly. That's why the new UDMA cards are a big deal. They eliminate the PIO bottleneck, use multi-channel flash controllers, write buffers, etc., and should outperform magnetic discs on just about any real workload (not on sequential transfer rate tests).