The CBs and Exports sound just as good as the HF Ham rigs on SSB, as long as they are tuned and operated properly. The FT-840 is pretty miserable sounding on AM, the Icom offerings sound better. My Galaxy DX2517 with Astatic TUP10DA mic sounds as good as or better on SSB than most of the HF rigs you hear on the air. But, then again, mine was tuned/aligned by SS8541, and I know how to run the thing properly, many exports and their operators are not so endowed.
The real difference between the Exports and the Ham HF radios is the RECEIVER! Under decent band conditions, not a big difference between them, but under heavy QRM or other noise, the HF rig comes into it's own. Better design, better filtering, DSP and all that can make a big difference.
If all you plan to do is talk 11 meter, I'd stick with the exports. If you have any interest in Ham, then get a nice HF rig for SSB, and a nice AM only or AM/FM CB or Export that has the big audio punch that the 11 meter AM band calls for.
Never expect one radio to do everything - you will always be compromising somewhere. I use the 2517 for 11 meter AM and SSB, and use a Yaesu FT-847 for everything else. I occasionally use the 847 for 11 meter SSB DX, mostly when things are getting overseas, that's when the superior receiver kicks in and helps me make more and better international contacts.