IMO it makes little difference what box you get,every make has had it's foibles.....and at the end of the day the STB's aren't "audiophile" quality products,they're budget CE equipment built to a price.
The Thomsons were by far the worst due to the PSU problems,and part of the reason they're no longer used for new installs.
The Pace were recalled for the "potential fault" and could be slow.
The Amstrads have had contrast adjustment isssues, though supposedly fixed with the New EPG.
The Samsungs have HDCP compatibility issues,and some had faulty IR sensors that meant if installed in a bright enviroment the remote signals couldn't be received properly,thus making the STB unresponsive. Some users are now also complaining of PQ deterioration since EPG upgrade.
The above doesn't mean each and every box is potentially faulty though!!!! It's just some of the problems that the different STB's have suffered