You received many good HONEST answers from my colleagues - sadly, not all real estate agents are honest about rent-to-own leases.
In the end it is YOUR decision to make; however, I would discourage that option. While occasionally those transactions do work out and result in happy home ownership, statistics do show that majority of rent-to-owns buyers do NOT purchase the home they contracted to purchase. The most common reason is that once the buyers' credit is repaired, they prefer to select a home from the large INVENTORY of homes now available to them. Also, there are very few rent-to-own homes available and most are overpriced.
Since your credit is good, I suggest you look at other options that will allow you to save enough for a downpayment. Did you consider taking at least temporarily another job which would allow you to save more money for the downpayment? Contacting Arlington County to see if you qualify for County loan programs is also a good idea.