Time for some comparisons.

Seems like Silversea, Seabourn, and RSSC all have about the same loyalty benefits for their initial members. Not sure what the referral coupon is on RSSC, but I know that SS gives you a $250 onboard credit when you refer someone that travels with you and they double your cruise day award so that you accumulate points faster. They also give your friends the same 5% or 10% Venetian Club savings if they are sailing with you.

Here are the areas that I see SSS excels in over the Silversea Venetian and Seabourn Club programs.

Once you turn Silver (21 days)
Free Internet (a biggy with me)
Free Phone Calls for 1 hr. (not such a biggy
for me)
Pressing on Formal and Informal nights (a nice
touch)

Once you turn Gold (75 days)
Additional hour of phone calls
Pressing
Complimentary Photo (I have a camera)
Spa Certificate (yes, I will take that
additional massage!!!)
Priority disembarkation (may or may not be a
big deal)

Once you turn Platinum (200 days)
Additional 2 hours of phone time
Bridge tour (again not a biggy. I think you
can do this on SS anyways, though we never
have.)
Free laundry (nice on longer cruises)
Liquor and priority reservations are moot,
since the liquor already comes on both and
reservations are not needed on either.

With Silversea and Seabourn the advantages are primarily larger discounts and free cruises.

At 100 days with Silversea you get an additional 5% discount on ALL cruises and that is in addition to all other discounts (including Venetian Club, onboard bookings, and B2B savings). Oh, and you get free laundry, but no dry cleaning or pressing.

After each 140 days on Seabourn you get a free 14 day cruise. (Now that is what I call a perk!)

At 250 days with Silversea you get an additional 10% off each cruise booked and early embarkation and late disembarkation.

At 350 days with SS you get a free 7 day cruise and at 500 days you get a free 14 day cruise.