IMO, RML is run by upstanding people. Clearing through Penson/GHCO. If you need the all-in-one account thing, RML is a fine alternative to IB and even MB. Plus RML negotiates, IB and MB do not.
I can recommend JPR Capital for stocks. I have had an account with them for nine years. Commission is 0.005 per share with rebates for providing liquidity and a fee is charged for taking liquidity. They are a small firm with great customer service. They clear through Terra Nova. Terra Nova pays currently only 2.5% on overnight cash balances which will be a negative if you have large overnight cash balances. Currently MB Trading is paying about 4.35% and Interactive Brokers pays a little less unless your cash balances exceed $100,000.00. I can recommend an account with all three of these brokers. I have not used RML Trading and therefore can offer not opinion on them.
RML is a good direct access firm as it gives many choices of softwares. You ask for a demo to see if you like them. Their option commission is bit higher than IB's.