“Which would you recommend?”

You're shopping for a laptop computer at a store. The salesperson has shown you two computers within your price range. You want to know which one he thinks is better. You say:

Which would you recommend?

(which/what) would you recommend?

Use this phrase when you want to ask an expert to help you choose something. For example, at a restaurant you can ask the waiter to tell you what items are best by asking:

What would you recommend?

You usually use "which" when asking for the best out of 2 things, and "what" when asking about a larger group of choices.