For premium cards, I've used Aubergine Print for years. I don't know how the price compares to what you've been using but I've never had a problem with the quality.
Their service is good and they ship direct to the customer in unbranded packaging.
Assuming you're printing for a client then you need to pass on that cost but be an advocate for the quality.
The best way to do that is to have your own cards done with a premium service then you can showcase why it's worth extra spending extra.
If I give an all-in price and the client thinks it's expensive then I usually offer to just supply print-ready artwork at my hourly rate. And they can do with it what they like, as I don't want to put my name to poor quality. When they realise they have to organise something that they don't really know about they let me handle it. But sometimes a client already has their own print supplier so that's fair enough.
Where it has happened that they take the files to vista print or someone, they sometimes come back and ask me to get them done once they've got through the first batch and realised what they got was rubbish.
FYI - I always expect to add a 20-40% markup to any print I handle.
