Choose a TV Card

Hi! I have used WMC for a long, and now I'm starting to use XBMC. TV scheduled recordings are important for me.

Now I'm testing under windows, because my TV card doesn't have support under linux, but I want to buy a new one and move to linux.

My question is: What must I bear in mind to buy a new TV card? One thing is that would linux-comtabile, but, What about this that I have read?

• Channel change speed
• Hardware MPEG decoder, Wha is this for? what is the advantage?
• Number of tuners
• What about DVB-T and DVB-T2? My actual card is DVB-T and I can see HD TV channels with it.
• What about image quality? Is tv card dependent?
  

Lot of thanks