They are very very similar machines.
Here is a website which compares the two side by side with pictures..
• For milk based drinks, the Silvia has a better steam arm.
• The Silvia has a tonne of support out there and massive cult following it.
• In the right hands theyll both last years and years.
• The Lelit does heat up significantly faster as the boiler sits directly above the group head - where as the Silvias is to the side.
• Lelit doesnt have the commercil 58mm group/portafilter (only matters if you want aftermarket stuff)
• The Lelit has a functionally large drip tray :)
If you do mostly milk based drinks maybe the Silvia is worth a bit of extra cash.
If youre not fussed about the steam wand then the Lelit will make just as good coffee for a cheaper price tag.
If you havent got bench space for a decent grinder - pick up a Lelit Combi.