Although I prefer reading with one deck, I've done this a couple of times.
This is what I've tried:
- Sometimes I'd do a spread with one deck, read the cards, cleared the table and would do the exact same spread with another deck. Sometimes I'd get the same cards from different decks, on the same spot! But in general, the second reading makes for a somewhat different one.
- I also would do two spreads (the same) side by side, each with a different deck, and would read it as a whole, it gives a more detailed reading so you will.
- I've also done two different spreads side by side with two different decks, on the same question, which gives a detailed reading with somewhat different perspectives.
- And I've also used a spread and after having drawn tarot cards, would draw oracle cards for the same spread, laying each oracle card besides the tarot card on the same spot.
- You can also use a spread, and then draw one or two cards (for example oracle cards, or just tarot cards) from another deck for more insight.
As you can see, you can do all different kinds of experiments, just use your imagination. The possibilities are endless.