it depends what you want and how much you want to spend
some of them are twin tuner so you can watch one channel and record another
some can handle cable, sat and iptv at the same time, but if you've no dish this probably doesn't apply to you.
As a starter, you can get a zgemma h2h which can handle cable, sat and iptv for about £70
a twin tuner H52tc is around £89
The Formuler F1 is another box that can handle cable, sat and iptv but I've never used one, these are around the £89 mark also