it all depends on what you want to do? cheaper boxes allow you to most things TV wise, so if its only tv then no need to spend extra. if you want to record and watch at the same time, then u need something with a twin tuner. satellite or cable ?
if you want to access decent iptv, then you need a good internet signal first before considering spending big bucks on something that really doesn't deliver BECAUSE of the slow internet.
do you want to run kodi etc - then you really need to be looking towards the high end spec
I think theres a thread running already on different boxes and their advantages/disadvantages. have a read before you spend your money!