What are some alternatives?
When comparing Roost and PushOwl, you can also consider the following products
PushCrew - Push Notifications for Websites
Pusher Push Notifications API - Send push notifications programmatically at scale
OneSignal - Customer engagement platform used by 800K+ developers; the fastest and most reliable way to send push notifications.
PushPrime - Supercharge your website with push notifications
iZooto - Engage your mobile and desktop web users with intelligent web push notifications.
Amazon Pinpoint - Targeted Push Notifications for Mobile Apps