I have had one since November. They do the job but they can be a little inconsistent. However I have not had any trouble with it.
Most here will say it is the bare minimum and will probably not work to well with the Silvia. I cannot comment on this as I do not own a Silvia. However you would probably be better off saving up and spending the money on one further up the scale.
You will suffer upgraditis eventually it is a disease that affects all who frequent the dark science of Coffee ::). I will be taking possession of a Mazzer Mini next week if TNT get their act together. >:(