I think a lot has to do with the build ( housing ) of the product and the components used within the speaker. Not to mention it might have a lot to do with the phones ability to broadcast using BT as well. I have a BT speaker that I use in my car occasionally and it works fine in the car. When I use it in the house it also works well but if I take into another room it sometimes will start to cutout but depends on where I sit it. Like what was said, the better the line of sight along with being closer to the phone the better it will work.

BTW, I plan on buying a BT speaker for the bike. Should be similar to the Buckshot but a cheaper Chinese brand. I rarely play music while on the bike but I do sometimes like to listen to podcasts or an audible book. Though I've never done that while on the bike I thought it might be interesting to try. I also like the idea that I can also charge my phone using the speaker if I use one that includes that option as well.

Anyway, if I get one that sucks I'll let you know. I mount my phone on the stem of my handlebars for navigation purposes though so I don't think there will be any cut-out issues. Of course with BT speakers there is always going to be other issues like lack of volume, tone issues and how well the mounting system works.