I recently went from being a firm believer that a great amp doesn't need any reverb at all to realizing that I like a splash of reverb on almost everything.
I bought a Malleko Spring to try on a couple of amps that I felt needed reverb and was amazed when I heard it with my 5E3 clone! It makes certain licks come alive!
Under close scrutiny, the Malleko Spring would never fool a spring reverb connoisseur, but, in the mix, it actually performs a little better than a real spring reverb.
Unfortunately, it does not sound great in front of a high gain amp like my Mesa Subway Rocket. It sounds great in the effects loop, especially with the reverb maxed and the effects loop level set low.