Would great if you could use else with the user:can and user:cant tags.
Otherwise you get this:
{{ user:cant do="edit projects collection" }}
{{ redirect to="{route:login}" }}
{{ /user:cant }}
{{ user:can do="edit projects collection" }}
{{ partial:app/estimate }}
{{ /user:can }}
Whereas this would be nicer:
{{ user:cant do="edit projects collection" }}
{{ redirect to="{route:login}" }}
{{ else }}
{{ partial:app/estimate }}
{{ /user:cant }}