The way that massage chairs are marketed tends to place quite a bit of importance on things like the kind of massages that these chairs provide, the power of the massage that you would receive from them as well as things like how long they would last in terms of durability. However, all of this marketing might distract you from perhaps the actual most important thing that you should be looking for as far as your chair is concerned: how comfortable it is to sit in.
The thing is, so many massage chair manufacturers focus so heavily on putting as many features into the chair as possible that over time they forget that the chair needs to be a comfortable chair to sit in as well otherwise it is highly unlikely that you would be able to get a good massage out of it no matter how comfortable it is.
What you should generally be aware of is how the chair feels when you initially sit on it before the massage begins. Does it feel like a chair you would enjoy using without the massage feature? A lot of things play a role in whether or not a chair is comfortable. You want it to be soft but not too soft, and at the same time you might want to try and look into good quality materials as well. The material should have a bit of a grip, something that would allow you to sit comfortably without sliding off every so often.
The good thing is that when you look into resources like https://www.healthnerdy.com/buying-a-massage-chair-what-to-look-for-and-is-it-worth-it/, you would find that there is a lot of information out there that is designed to help you buy the very best massage chairs.