I bought this to replace my 20S. A big selling point for me was the mesh technology and the fact that it fit on the same base unit as the 20S. I have two helmets that I go between, so I put the newer base unit on the helmet I use more often and the base unit from the 20S on the other.I can't give an opinion on the HD speakers because I use earbuds with mine. That way I think I get better sound, and I get the benefit of noise reduction. The speakers on the 20S were crap.I gave the Sena 50S 3 stars overall mostly because of the "bugginess"...Pros:The mesh intercom sound quality is great. The bluetooth intercom is pretty good, too.The iPhone app has a cool setting called "Smart Intercom Pairing" that allows you to quickly pair to another 50S or 20S.The iPhone app overall is better than the app for the 20S because it is more intuitive, though I would prefer that Sena create a single app that works for both. I would recommend using the app to set up the configuration of the 50S; you can do it on the device itself, but it's more difficult. For sure don't try to change the configuration while you're riding.The battery life in bluetooth intercom mode is said to be 24 hours. I've had mine powered on and connected for over 12 hours before with no problem.The flexible mic that comes installed on the base unit has pretty good noise reduction, but I thought the mic on the 20S base unit was good as well. However, it can only do so much noise reduction when someone is riding with an open face helmet with no windscreen at 75 mph.Cons:In mesh mode when you're trying to listen to your own music, the mic sensitivity is too high even when it's set to the lowest sensitivity. I was riding with two other people who have the 50S and I couldn't hear more that about 20 seconds of music before someone breathed too heavy and muted the music. There is a setting that you can turn on that will prevent the music from muting, but then you end up having a hard time hearing what someone is saying over the intercom when your music is playing.Setting up group mesh is a little confusing so read the instructions thoroughly. I would recommend setting up your group in advance of your ride. It’s more difficult trying to figure it out while you and your buddies are sitting on your bikes and yelling back and forth under your full-face helmets.The button on the 50S that turns mesh intercom on/off (press and release) is also the button that mutes the mic (press and hold for 1 sec) and it's on top of the 50S right next to the antenna. It is almost impossible to find and manipulate the button when you're riding and wearing thicker gloves. I think it mesh mode, especially in group mesh, it would be MUCH easier to press and release the jog dial to mute/unmute the mic, similar to how you start an bluetooth intercom conversation.The battery life is cut by a 2/3 when you're in mesh intercom mode, so after 8 hours, it’s time for a recharge.The music-sharing function when in mesh mode is a cool idea, but in reality I found the sound quality subpar and it kept cutting in and out.The firmware is still fairly buggy. I always have the most recent Sena configuration program on my iMac as well as the most recent app on my iPhone and I have the latest firmware on the 50S. And I always have my iPhone OS up-to-date. Sometimes I will randomly lose the bluetooth connection to my phone. When I checked my OS bluetooth settings, it says it’s disconnected and it the Sena app also says I’m disconnected. It's a pain in the @$$ when it happens while riding. Some people may point to the iPhone as the root cause, but I have a number of bluetooth devices connected to my iPhone and the Sena 50S is the only one that gives me problems.Overall my recommendation would be this…if you and your riding buddies have Sena 20S’s and 10S’s, and you find that everything works to your liking, stay with what you got. I had no issues connecting my 50S to 20S’s and 10S’s via bluetooth.Update - 05/19/2021:I’ve been using the Sena 50S now for a few months. I stand by my original review with a few updates…1) When you’re in Mesh mode and listening to music, the mic is always on. Even at the lowest sensitivity, wind noise or heavy breathing will still trigger the muting of my music. The setting that prevents the music from muting is nice, but you then you constantly hear wind noise, etc. while listening to music. It is a bit difficult to have a conversation with people while music is playing at the same time.2) Connecting to the other people in my group in Mesh mode is easy. Just turn on Mesh mode, and within a matter of seconds everyone is connected to each other. That’s very convenient.3) The speakers…my bike is loud, so combined with wind noise while riding, I need to wear hearing protection. If I wear the cheap foam earplugs, then I have to crank the volume to 11 to hear my music and the intercom. I found a company that makes special foam tips from my earbuds that does a pretty good job with lessening the noise when riding, but then I have to contend with cords, earbuds falling out when putting on my helmet, etc.4) Battery Life: In Mesh mode, you have 8 hours, period. In regular bluetooth intercom, you have 24 hours…unless you’re listening to music, then you’re down to 12 hours.5) Bluetooth Intercom VS Mesh Intercom: If you’re in a group of more than 2 people, then I think Mesh intercom is the way to go, even with the drawbacks I mentioned earlier. If it’s just you and a buddy, bluetooth intercom is fine. You don’t have to worry about “single-clicking” to talk to person A, “double-clicking” to talk to person B, “triple-clicking” to talk to person C. (Read the directions if you don’t know what I’m talking about).6) The firmware seems to be better. I’ve updated mine a couple times since my original review, and I haven’t had the issue with my Sena disconnecting suddenly while riding.7) If you are new to Sena intercom devices, I recommend practicing how to use it while riding. In the safety of your home, put on your helmet and riding gloves (if you wear them) and get a sense of how to use your Sena.