Im a retailer/ecommerce seller and i sell quite lot of new products every month or so thus will need to create new links constantly for each new products.
I do not have much experience with link shortener but this link shortener does meet my current needs. I havent use the custom domains yet.

My use-case is using this link shorterner to shorten my product links and i will share the link to my social media and monitor the analytics

Here what i like about it
Simple UI and easy to use
The main limit is only Number of URL for statistic (can replace old links with new ones)
Link Preview for most social media
Link Preview Customizer (Add title, Description and Picture)
Preview autofill based on link
Link Statistic detail include Browser, Devices, OS, Cities, Countries & Total clicks + Click in the last 24h/week/month
Link Statistic comparison with other links
Custom Link back-half (Link look nicer)
Beside Statistic limits, domains and team members; the rest are unlimited

Here what I do not like about it
Deleted link seem like it not renewable?
No link preview re-editing (can only create new link)
No Folder, No tags (cannot organize/sort all of the link only can search)
When opening the shortened links before completing loading the destination page; the page title on the tabs show "Test Title" they should change it to "Redirecting"

What i suggest they have to focus on to improve it
Allow re-edits (Dynamic Variables for links, title, description, picture)
Allow Bulk link import
Add link retargeting (Pixels)
Add UTM Builder
Add link redirecting (404 Error Redirect)
Add link rotator (A/B Testing)
Link analytics show which sources/social media user come from either FB/Insta/Websites/Ads
Messenger Links/Deep Link
Add Chrome Extension (Allow any links to be quickly shortened anywhere)
Add Folder/Tags & Allow reorganize the arrangements of links

Piar.Io is lacking some important features for me but since the limits are acceptable to me, I will try to stick with it, really hope they implement my suggestion.
The reason for 4 tacos is because of the lacking features, with this pricetag it should provide abit more features.
Compare to switchy, switchy seem better but switchy click limit really limiting for me.
So far overall, Piar.Io is okay for my use-case. If you need to create new links constantly and advertise it then monitor the link analytics; then this should fit you, you can turn off analytic for the link once the campaign for the link ended.