Strengths: this speaker, while obsolete, is well constructed and can provide a coherent solid sound that's easy on the ear and doesn't fatigue. Pairing two as a stereo pair can be rewarding.
Weaknesses: their Bluetooth implementation is 'of an age', and the stereo pairing implementation is an early one - they may sometimes struggle to work in an environment with many other devices using the 2.4g radio spectrum. The speaker may not work well with particular devices - for example, a pair working in stereo may struggle when paired with an Apple laptop running MacOS.
Finally: the USB charging port they provide should not be used as its use to charge modern devices is liable to permanently disable the speaker's internal battery (and may well be the cause of the reason you've needed to replace the battery).