Depends on what you want. Jump-In offers a lot of value with 2 rares per 1000 gold and its always an even match since your opponent is always playing jump in. If you want to build a specific deck, playing constructed and buying packs will get you wildcard/gold pack prizes for the rares you’ll need. Drafting is the most gold eviction if you’re good, but you should make sure you have the fundamentals down and look at a drafting guide for the current set.