Types of Radar

[paul]

I'm looking to buy a radar detector here in the States for a mate in the UK. He is being recommended the Bel Euro 550 (about 320 quid) but the nearest one to that over here seems to be the Bel 990 International (about 300 bucks).
The only difference I can see from the specs is that the 990 doesn't support Ku band. Is this a big deal? Depending on what you read its either obsolete or essential...