One Naruto with a cooler design and a new set of abilities. Sage Mode is a very difficult technique to acquire and master in the ninja world of Naruto. Very few have been able to use it, and Naruto is perhaps the only character to have mastered it. This could quickly change, though.
Sage Mode is achieved through aligning one's own chakra with natural energy, creating senjutsu chakra. It grants access to new abilities as well as enhancing known techniques and physical capabilities. Sage Mode also changes one's look to resemble the animal that taught them their branch of the power. This is not to be confused with Sage Transformation, the kekkei genkai of Juugo's clan that allows them to ively take nature energy and use the senjutsu chakra to transform parts of their bodies. Mitsuki uses Sage Transformation to achieve Sage Mode, and in a more perfect state than that of Juugo's clan.
Being a clone of Orochimaru grants Mitsuki access to Juugo's kekkei genkai, as well as the 1st Hokage's cells. Using Sage Transformation, Mitsuki's body takes on the clan's usual cosmetic change, and the 1st Hokage's cells automatically align Mitsuki's chakra with the nature energy, enabling him to enter Sage Mode effortlessly. Mitsuki's look changes to more resemble that of Naruto's chakra mode, and he also manifests transparent snake spirits that float around his body and protect him. Mitsuki being able to achieve a state like this at his young age makes him a great future matchup against Naruto, but it doesn't come without its faults.
Mitsuki being artificial rather than natural allows him to access Sage Mode quicker, but this also works against him. Constant use of the Sage Transformation to power Sage Mode puts too much strain on Mitsuki's cells and causes them to break down faster and beyond repair. In order to survive, Mitsuki has to be put on life and have new cells implanted into his body. As the story of Boruto continues on, this could be something that Mitsuki and Orochimaru work on and improve.
Despite its drawbacks, Mitsuki has a cooler and more efficient Sage Mode than Naruto. The design has more flair to it and has additional powers, the range of which still remains to be seen. Mitsuki's Sage Mode is just in its beginning stages in Boruto, but if he keeps up with it, it could potentially overtake Naruto's.
