I'm going to submit the same review for all three speakers. The reason I'm doing that is because my plan is to use them in my backyard around the pool in a party/group configuration.Each speaker has its pros and cons obviously. But I'm going to speak about the size, weight and sound compared to each other. All three have excellent build quality and look really sharp. Each has a really nice fabric accompanied with rubberized plastic that's easy to grip. Each unit also had a nice heavy/dense feel to it. I'm assuming that's attributed to battery size, considering the runtime that these are stated to have. I have not tested the endurance of the batteries yet but will follow up with that as I know more.SRS-XE300 X-Series: this one really punches above its weight. The sound for such a small speaker is actually really good. And it has a surprising amount of bass for its size and the clarity of the treble is wonderful. The configuration of the speaker openings are quite strange on this model, and you wouldn’t think it would be effective but it really sounds good but correct physical placement of the speaker is the key to get great lows-mids-highs from this. I was quite surprised at the quality of sound for the lowest price.SRS-XG300 X-Series: this is a nice sounding speaker and it really has a great size and weight to it. I was a little disappointed as I thought that it should have had a lot more bass compared to the SRS-XE300 but it does have a sufficient amount. Maybe the smaller XE300 just surprised me with the amount of bass that it has? I ordered a package unit that included a case that is of decent quality. The nice part about the case is that it has a small compartment to house the included USB C charging unit.SRS-XG500 X-Series: this thing is really stout and gets really loud if that's what you want, while still sounding great. For a speaker the size of an old style boombox, the bass will thump your skull. One of the cons for this model is that it doesn't charge via USB C. It uses a barrel tip charger while the other two use USB C. It would be nice if Sony made them all consistent. And compared to the other 2 speakers, this one feels like the battery isn’t as heavy in comparison to its size. Not sure if that will impact battery life as I’ve not tested that yet.The first time I tried the party/group speaker configuration the sound volume was imbalanced out of each speaker. The way to rectify that is to turn the volume to zero on your Bluetooth device after you've created the group to level-set their volumes at 0. At that point all of their volumes should stay in sync when you volume up via Bluetooth.Full disclosure, I bought the XE300 and the XG500 refurbished. The XG300 was brand new. The refurbished models that I bought were in excellent shape. I would recommend powering them up and playing them for 4-5 hours to make sure that they are in good shape after being refurb’d.