Up Front Costs
10 S3 at 4.5TH/s is 3550 watts. 5.8BTC + PSUs.
1 SP30 at 4.5TH/s is 3000 watts. $3895 + $300 shipping
Advantage: S3
Hosting
10 S3s, plus PSUs, lots of cabling, non-standard design
1 SP30, 1 network cable, 1 power cord, standard rack design
Advantage: SP30
Maintenance
10 S3s, individually configured, or creation of generic deployment scripts, individually managed firmware updates, or scripted, have to hunt on Bitmain's website to see if new versions are available
1 SP30, individually configured, individually managed firmware updates with clearly visible new version notifications
Advantage: SP30
Support
10 S3s, support handled through web-based tickets or email. Long turnaround times and RMA through China.
1 SP30, direct support from Spondoolies-Tech staff including using TeamViewer to diagnose and troubleshoot problems directly on your machine.
Advantage: SP30
Time to Market
10 S3s shipped on or before 9/20
1 SP30 shipped end of September
Advantage: S3 (depending on how much before 9/20 they ship and what "End of September" means for SP30)
Disaster Recovery
10 S3s, losing a unit only costs 10% of your overall hashing speed
1 SP30, losing a unit costs 100% of your overall hashing speed
Advantage: S3
Conclusion
While the SP30 wins out in ease of deployment, support and maintenance, it loses on cost and potentially on time to market. In favor of the S3 is precisely their ability to be spread around. Use them as space heaters in the cold months, add a few more here and there to compensate for difficulty increases. They can be reliably run at rated hashing speeds on 110V power. The SP30 loses speed on 110V power due to PSU and firmware limitations. You can test your luck and try to override those settings, but you'll void your warranty.
For data center deployment, the SP30 is the flat out winner. The standard rack design works very well with high-density cabinets. There's only a single machine with a power cable and a network cable. The data center only needs to worry about managing a single IP address and providing remote access to the web-based configuration interface and direct SSH access can be controlled easily.