Not being encumbered by patents is a huge advantage for MP3s going forward, and the reality is that MP3 is good enough for vast majority of situations. The improvements newer formats like AAC bring are not worth the trouble of being chained to a proprietary format.
I was a flac snob when I was younger, and I can say with certainty: 320kbps mp3s or even VBR are indistinguishable from opus or even lossless except when listening very very very closely on high end hardware. I'm very into audio still and production etc. That's not to say opus isn't better or higher quality, but the difference it makes is decidedly negligible to the vast majority of listeners. I guarantee that almost everyone would fail to do better than a coin flip a/b testing these technologies on the same audio recording.
192kbps opus will allow you to achieve roughly the same quality as 320kbps mp3. If you stream your music from any device or have a larger collection this difference can matter a lot.
As a music producer, you notice 192k MP3. The next jumps you probably don't notice. I'm still a flac snob because I have to work a lot with original quality files, but for the average users there's probably not even a difference between MP3 192k+ and flac or wav or opus or whatever.
I'm not sure you can go more than 320kb/s on mp3. I have my music collection on my home server in FLAC but I transcode to 320kbps constant bitrate mp3 for my car and phone. I chose 320 because it's the highest that I've seen mp3 converters able to go.
Basically it goes a little like this... I bounce out a song as a WAV, and then convert it to a 320 MP3 using iTunes. iTunes compresses very well (imo), and so if you compare that WAV with that 320, they will sound practically identical. I then take that 320 and Convert it to 128 in iTunes. The sound is STILL practically identical. (Because it is a good 128.) There may be a little rolloff around 8-10k (super high end) but it's more of a "sound change" than a "degradation". This conception that 128's are drastically inferior to 320's mostly comes from 1. people reading bullshit on the internet, & 2. people downloading BAD 128's!!!! Seriously. Not every WAV is equal, not every 320 is equal. I could take something at 92 KBPS and rebounce it as a WAV. does that make it a lossless audio file? Fuck no. Who knows how many times it' been downconverted/upconverted etc. Just because you downloaded a rip on /xtrill and its a 128 and it sounds bad doesn't mean 128's sound bad. Just because the apple I bought was rotten doesn't mean all apples taste awful. Basically if I listen to a song and it sounds good, I will play it. People knock me for playing 128's and I'm just like... If I can't tell the difference, then neither can you. And the bit about playing it on big systems and it sounding like shit is also a load of crap. TL;DR: If it sounds good on good headphones, play it. (That said, anything below 128 and you will notice audio quality deteriorate VERY quickly.)
I did the same. Faced a problem where mp3 and opus replaygain tags follow different spec (replaygain calculators for some reason use R128_ tags for opus files for some reason) and some players don't support it yet. Apart from that there haven't been issues.