I'm comparing the 4 cup Musa to the 6 cup Moka Express. First, the Moka Express takes roughly 3 oz of fine ground to fill while this Musa takes about 1.5 oz to fill. If you follow the directions, the end product for the Musa will be very weak compared to the Moka Express. I've learned that even though the directions say not to tamp the grounds, I lightly tamp the grounds to get a little over 2 oz of ground to make a product with the same potency as the Moka Express. The brew time will take a little longer, but worth the wait.
With that said, it all comes down to how the end product taste doesn't it. The Musa may win the looks contest, but the aluminum Express version wins on taste. Not sure how and why they taste different, but I did a taste test with friends and all agreed that the Express taste better and it's cheaper.
I would say get this if you a have fear of aluminum products and still want the Moka experience. I would pass on it if you're looking for a better product than the original Moka Express. For that, I would recommend you try the Aeropress, it takes more grounds, but the taste is worth it.
Would I buy the Musa again? Yes, it's another weapon in my arsenal for java nirvana. Although it may not be the most tasteful I have, it works great for 2 people having 2 shots each. Also, if you've never had the express version, you won't know what you're missing and this is a very good substitute. One last thing, it's very well constructed, you can see and feel why it's more expensive than the aluminum version.