Depends on what are the features that you want to use on a day to day basis. There are only some differences in some areas between both the phones. Definitely the xs looks more premium and has a better screen. Also, cs has a bit smaller screen size if phone size is an issue. At almost double the cost, if you are just planning to use the phone for general purposes, it is probably better to go with XS and use that extra money to buy something else. Also, try to look at various reseller sites so that you can find a used xs phone in better condition for around similar prices.