IMO I would bid the minimum for a sky suite. The experience is worthwhile. You get access to a great lounge and Luminae the restaurant is superior. You also have priority boarding, seating etc. The cabin is so much more comfortable. More storage- While others might disagree, spending time in your cabin is worth it. In a great cabin, you can enjoy breakfast on the balcony, drinks and snacks and concierge assisting you.
If your budget permits, do it! You will not regret it.