Can set_transient() be used in multi-site?

As the Codex suggests:

Essentially the same as set_transient() but works network wide when
using WP Multisite.

One difference is that the transient name should be 40 characters or
less in length. Also, while set_transient() sets transients that have
an expiration time to not autoload, all transients added with
set_site_transient will auto-load at all times.

In other words, the fundamental difference is in the auto-loading and since transients might be serialized, you could risk breaking things if referring to a blog (in MU) which has different settings/url/etc.

So the short answer is:

• use set_transient for single blogs

• use set_site_transient when you need something for ALL blogs.

Example of stored transients: