i owned a pair of mirage frx-7 ($700 retail) which i used for music. i also had an entire frx package for home theater duty as well. mirage speakers overall were decent, but your estimation of mid-fi is correct in relationship to my experiences.
i haven't heard the omd-28, but it's my understanding that it's their flagship speaker so i presume it's better than their other offerings which i'm more familiar with. my previous gershman avant garde's fully trounced the frx-7's and my current von schweikert db99 do the same. of course, these are multi-thousand dollar speakers compared to the $700 frx-7 so it's not really a fair comparision.
if i were you, i'd at least give the omd-28 a listen if possible. based on my experiences, if i didn't have the chance to demo, i would continue looking elsewhere.
i haven't heard the omd-28, but it's my understanding that it's their flagship speaker so i presume it's better than their other offerings which i'm more familiar with. my previous gershman avant garde's fully trounced the frx-7's and my current von schweikert db99 do the same. of course, these are multi-thousand dollar speakers compared to the $700 frx-7 so it's not really a fair comparision.
if i were you, i'd at least give the omd-28 a listen if possible. based on my experiences, if i didn't have the chance to demo, i would continue looking elsewhere.