Platform doesn't really matter , commissions id say yes if you trade volume, what matters is execution.
That's why we offer not only DMA, but also option algos. Also, access to the complex order books, and for larger accounts, access to floor brokers.
Wow, wow, wow, where did you get that Penson nonsense from? Penson brokers sell order flow day and night. OptionsHouse is a broker that clears Penson and they sell all their order flow. OptionsHouse 606 for the quarter ending 09/30/2011 is here for all to read: http://www.optionshouse.com/asset/pdf/quarterlyreports/20110930.pdf
They have their own routing, so they can sell their order flow. Penson has their own routes too. Not all brokers do. It has nothing to do with Penson. Very few firms that control their DMA don't get PFOF. Every discount online broker does. My point was that the brokers don't sell the order flow unless they have spent money on the pipes that provide DMA.
Your never going to a guarantee that's absolute. You should always use institutions that make you comfortable. The reality is that if your a "customer", not a BD, at Penson you'll have SIPC and excess SIPC. Penson has plenty of excess capital and just sold a foreign sub for over $30MM to add to that. They are cut expenses to become more profitable and the most important fact is that the DON"T have a trading desk. All of the Prime Brokers that failed, LEH, BS and MF Global, all had problems because of excess risk and leverage in their prop trading, not from losses from brokerage activities. More than half our client are at Penson and choose to be there.