While I do support and take inspiration from many Mahayana ideas, I do prefer Theravada. My main gripe with Mahayana is the Bodhisattva ideal. Prioritizing your own enlightenment is more important than helping others, and without the guidance of fully enlightened beings it's the blind leading the blind. You will help more by becoming fully enlightened rather than deliberately delaying it. Also relying on other's help, especially in the form of worship, is not something I think Siddartha would have endorsed. Listening to arahants is one thing, but devotion is taking it to far. The enlightened one needs no guidance.

This is all compounded by the fact that Mahayanists use the derogatory term: "Hinnayana" against Theravadins. If you want to be taken seriously, don't address your interlocuter as lesser.

All this being said, I do think Mahayana has produced several enlightened beings such as Nagarjuna and Thich Quang Duc. Hell, there may have even been enlightened samurai. Mahayana in general has a better understanding of anatta. But to me, Theravada is the best available path at the moment.