I might have said guitar unless your goal was classical music or Jazz if it were still 1967 when I started. Back then, the role of bass was limited, though it did provide a door few wanted to take to get into a music college or maybe to get into your buddy’s already formed garage band.

Now there are many great bassists, many recognized bass parts and the role of bass is understood even in scientific studies. It’s vital and it’s not just a guitar that’s missing two strings. The whole technique and feel are different. That means that smart bands get a good bassist who understands the music, the audience and the feel necessary for what the band is playing.

You can learn guitar by ear and memorize songs. But I think you’re better off learning the theory and more advanced technique there as well. This means mastering several styles … not just say your favorite sub-genre of rock … and even being able to play “songs” as we old people put it (that is, the melody over the chords, not just a one or two-note lead line or the chords in a rhythm sense).

It would be easier to take on just one or the other to start with. Now that many view them as very separate instruments and techniques, you’re better off mastering the one you want to play. Granted, at higher skill levels (Jazz for instance), sight reading for guitar is more of a challenge than with bass. But at the same time, theory, composition and arranging are pretty much the same no matter what you play.

Meaning: don’t take bass because it seems like bass ought to be easier. Or guitar because it can be an easier road to recognition. Take the one that somehow makes sense to you and work it!

Can you play both? Sure — I have for 50 years. But I have to tell you that as others have posted, I did tend to horribly overplay bass in the first couple of years. And if I had it to do over again, I’d have stuck with one or the other. I was a lot of people’s favorite 2nd call back in the day. If the top guy wasn’t available, “call Phil … he can sit in and fit in … but he’s just not quite THE guy for XYZ type of music.”

If you're going to learn bass, take a shot at the double bass including at least competent ability with a bow. In the end, you will likely favor one or the other (bass guitar or double bass) but ability on both can take you far. They’re also two very different instruments in many ways, with their own techniques.

Bruno Mars has done really well over the past decade. He has a lot of good singles and has cemented himself as a music legend. But the thing is that he isn’t gonna reach Michael Jackson’s level at all.

Why would he be the next Michael Jackson when he can make his own legacy and be the one and only Bruno Mars? To be at Michael Jackson’s level, Bruno would have to sell millions of albums.

So for Michael Jackson, he sold millions and millions of albums and had a huge catalog of songs which made #1 consistently.

In fact, Thriller is the only MJ album that has sold 66 million. Meanwhile when you look at Bruno Mars’s catalog, his most sold albums was Doo-Wops and Hooligans and Unorthodox Jukebox with 6 million each. 24K Magic sold 5 million. Bruno only has 3 albums so far with 27 singles. Out of the 27 singles, 5 songs were #1.

So the answer is no. He isn’t gonna reach MJ’s level at all.