Massage chair preference is quite personalised actually, so it's better to bring your parents to try. When we were looking for one, my wife and I tried Gintell, Ogawa and Osim at MV and then settled with Ogawa.

We couldn't stand the foot massage on Gintell (a bit painful) but body ok. Osim feet massage and the "four hand massage" was ok ok so in the end we went with Ogawa. My friend uses Osim but his is the highest end one and he seems happy with it.

It's how comfortable you feel with their pressure, mode settings and their movement so it's best to try them out.

One thing about spec is you can ignore the Bluetooth music function so don't get suckered into getting one. The sound quality is quite shit and in the end, your parents just can just use ear buds for better sound and noise cancellation for better relaxation or just use tv speakers.

In terms of maintenance for Ogawa, if I remember correctly they gave 4 free maintenance. So far, no issues for me to get them to come over to do it.