Most portable speakers are average at best. Don't rely on the music that they demo on them in the stores because they always use music that represents the speakers best attributes. That said there are decent (not great) ones out there if you want to pay the price generally over $300.
I also would not buy one that is Bluetooth only. Make sure it has the capability to plug your phone/laptop or whatever is generating the music into the speaker as the sound quality will be better than using Bluetooth.
You will also find the range for the Bluetooth will be limited so walls and distance will interfere meaning if you are using a phone or iPod and walk out of the room with it you will lose the signal. 25' would be pushing the limits for most speakers.
Pairing shouldn't be a big deal once set up. Many Bluetooth portable speakers have open networks meaning anyone with a Bluetooth device can walk up and pair with the speaker. This would be a problem if the range was long but portable speakers just don't have a great range.