My wife and I each have a sena X1 helmet, purchased simultaneously in mid-September, 2020. The main purpose was to avail ourselves with the helmet-helmet intercomm, enabling voice/audio for safety and general talk while bicycling.
On the plus side:
The helmets fit well enough. The audio quality is remarkable. While wearing the helmet, one thinks that bystanders can hear the audio as clearly as the wearer, but in reality the audio can only be discerned with a foot or so of the helmet wearer.
One of the helmets failed to intercomm pair after 3 months. Considering I reported the problem on Christmas Eve, Sena's response and replacement was fairly punctual.
On the negative side:
Sena did not send a helmet return shipping label, nor did Sena charge us Sena's contracted shipping rate (with their shipper) for the helmet return. It was on us to pay retail shipping to return the pair of helmets before Sena would ship the replacements. The retail return shipping was a whopping $40. Sena you could/should do a lot better than this. That shipping cost is nearly 50% the cost of a new X1 now. Please work on this.