TL;DR: What to buy?

This is hard to know, since the market seems to not care about the fundamentals.

I would start by split up my portfolio into:

40% Ethereum (ETH)

40% Bitcoin Cash (BCH)

20% Monero (XMR)

Next up Step 1: Where to buy?

Why not Bitcoin (BTC)

I was blown away when I discovered Bitcoin in 2011. I was able to send Bitcoin to anyone with very low fees, a system where I could transact with anyone I wanted, without a third-party that needed to approve it.

Many non technical people do not know about the scaling debate that have been going on since 2014. It ended up splitting the community into two camps in August 2017, those who wanted to scale on-chain and those who wanted to have layers on top of Bitcoin.

One of the scaling solution that was sold was Segregated Witness (SegWit) and the other was Lightning Network (LN).

SegWit was introduced in August 2017, have done little in practice to increase the transactions per day. See chart

The adoption of Lightning Network is very low and suffer from design problems and being fragile. In order to use LN, you need to lock up BTC before receiving. Acording https://defipulse.com/ the BTC that is locked up is much lower than many of the ETH projects that use wrapper BTC in their contracts.

The end result is that the more people wanting to transact on BTC, the more expensive it will get. Those who pay less than the averge will have a slow and unreliable experience. Below is the average fee for sending a Bitcoin transaction.

Today the average is $14, when you are reading: https://bitinfocharts.com/comparison/bitcoin-transactionfees.html#3m