Quick summary: All in all the merge went splendidly! At first there was a participation % drop from 99% to ~86%, but this was due to a few minor bugs in Nimbus and Nethermind clients and the rate is back up to 99% now. There was also a minor bug with some client pairs proposing empty blocks; this will be worked on in the coming weeks.
If you’d like to participate in testing the merge, you are encouraged to send transactions on Ropsten, use dapps, and attempt to run clients!