l1- I'm not too sure about 'upscale' in BE, we'd probably say upmarket
l2- comma after 'inches'
l3- 'fatal defects'- how about serious flaws?
l4 brightness and definition are not high enough
l6 its size takes up too much space
l2 on a wall or even a ceiling (you could use 'the')
l5 cannot make it as big.... due to technical limitations
l1 avoiding the defects of both-
l4 take out 'very'