If it isn't a Sky digibox your after I suggest you get a Humax,I have a Humax 8100 PVR myself and it's very sensitive compared to others I have tried.
I read a post in another forum about a dx guy who had 5 different recievers,a Nokia 9900 or 9902 or 9802(can't remember which one),3 others and then a Humax 5400.His 5400 had by far the most sensitive tuner.
Some dx:ers use Nokia models with the 1026a tuner but I think they use the Nokia's most because they can use the DVB-2000 software with them.
Don't do the mistake and buy one of those cheap Chinese made recievers,
they often have a very bad tuner.
I also have a Coship 2300a and the tuner is very bad compared to the Humax,in some ways I guess you get what you pay for.