I would have thought quality gear would have been OK - the wireless chip scanny uses was developed intially by a division of GEC-Marconi (their Essex based EEV division) which did a lot of commercial spin offs from defence work, was possibly over specced and/or benefited from the input of the sort of scientific genius probably far more than is needed for the average 'consumer' product.
Texecom is a lot newer so no doubt designed with 4G in mind from the start, whoever the RF chipset provider.
However, perhaps Honeywell gear, although I'd have thought it decent, has it's RF origins in a US product that just happens not to be going down so well with 4G?
Risco, I have no idea.
That's all totally off the top of my head. Chinky stuff will undoubtedly suffer the most, even if the RF IC sections are blatent clones of EU designed chipsets.
of vague interest - http://rsgb.org/main/files/2012/11/EMC02-final.pdf