Yes, I am BTC only. After witnessing three bear markets and reading dozens of books on bitcoin, history, and economics I concluded that Bitcoin is the best investment on the planet by a large margin.
XMR attracted me for a time in the sense that it's supposed to be private, a feature BTC hasn't ironed out yet. There has been some speculation around that, but I don't have any evidence either direction. The fact that I know what Fluffy Pony looks like is problematic in itself.
What I do know is that XMR has a blockchain bloat problem (ZEC is worse), the full UTXO set cannot be audited, there is not a supply cap, and legislators are going to attack the onramps to XMR in particular because it is a lightning rod for illegal activity.
The first three issues are technical facts. The last one is a game theory issue. Regardless of ones ideology around the state it's clear that major investors will steer clear of XMR and it will never attract the kind of capital that BTC will.
I'm always open to a discussion, but I have had this discussion many times already so forgive me if I don't engage beyond this message.