Hi @Shubhreet,
It's pretty stable, and if you are using it with ArcGIS Online + Survey123 with Microsoft Power Automate, the setup is easier than using ArcGIS Enterprise + Survey123.
Our approach of using Power Automate + Survey123 is to use "Power Automate per user plan" to run unlimited flows using one centralized Microsoft account, and also manage all automations using this account as well. We have 2FA setup for the user, and we also make sure multiple users (IT & GIS) can manage it anytime with security key. This is the best approach for us, but maybe not for you.
You will also have to "refresh" your Survey123 connection every two weeks by reentering credential of the account. The maximum life of access token is 2 weeks by design...so make sure that you set up reminder on you and your team's calendar to refresh before your conneciton is expired.
Moreover, if you're ArcGIS Enterprise user, you need to make sure that Power Automate can reach your "Portal for ArcGIS" from internet. Your IT need to make sure of that. If you have reverse proxy, you need to make sure reverse proxy is funcitoning properly to allow Power Automate to reach to the portal for connection. If you have corporate firewall, you need to make sure that Power Automate can reach to the portal as well.
Finally, please make sure that you do not always use the "latest" version of Survey123 by default of your survey, if it's a very critical online survey/form for your organization. It happened to me that the latest update may cause issue of your survey. However, Esri got it resolved in a week...but we might be lucky like this everytime. There are some trick that you can use Survey123 Beta or url parameter to load "older" version of your survey (version here means Survey123's version such as 3.17/3.18/3.19 etc.).
I have shared what I have been experienced so far using Survey123 and Power Automate.
Bonus point here, to use Survey123 Create Report Action, it will cost you ArcGIS Online Credits. However, if you are using it with ArcGIS Enterprise, you do not need to use any credits. I believe it doesn't cost much...but you better double check with your Esri Account Manager. If you're planning to publish your "surveys" publicly, you will need extra technique to make sure security/access token can still be generated for your need.
Also, you may want to learn deeply regarding how to handle "attachments" from Survey123 using Power Automate. Survey123 has created so many tutorials or blog posts to help people understand how to do it using OneDrive as @IsmaelChivite has taught me so much from his posts.
You can and should compare other "form" centric on the market, but usually many organization has Survey123 included as part of their enterprise agreement...so why not take advantage of this existing powerful solution that you have already paid for. It's also an opportunity to show your organization that GIS is not just "mapping", it's far more powerful than that!
Hope this help a bit 🙂