Not really. The OBi202 is capable, efficient, and economical. Unless you have a specific need, I'd stick with what you've got. Maybe add a UPS or prepare a spare ata for backup.
IP phones have stronger call handling features?, better sound quality?, and cost more. They may also require more distributed admin and more network access and more costly spares.
Newer DECT 6.0? wireless phones might enhance your current setup, but could add unwanted cost and complexity.
You could try one IP phone to enhance a home office and to experiment.
You could deploy some softphones on mobile devices as mobile extensions.
OE