I have not presonally used them, but I stand by saying that you should always submit your own website. then you have nothing else to blame buy yourself if it fails. Take the time and submit to everything you can find, I use a program called roboform to automatically fill out any forms that I need.
I haven't tried those kind of services other than using their seo tools. Just like others may say I rather do it by myself manually.
Submit Express knows what they are doing. They don't accept your money until they produce the results they say they will. Their URL submission tool is just something to make their website sticky... SEO is their business and they know their job. I really don't believe in a monthly "maintenance" fee which the SEO industry seems enamored with... I have always preferred charging a flat fee for consulting services and having the user do the work themselves. Paying a huge monthly premium to "maintain" the position they have achieved for you is a scam and only serves to keep their knowledge of how you achieved your position a secret known only to them. ie you are in the dark about what it takes to get your site to the top and cannot opt out of the company's services or you risk ruining your business because you don't know what they did for you. In the end you will definately see results from Submit Express but is your expected ROI enough to pay them each month? I guess it depends on your industry but judging by the affiliate link you have in your signature I would have to say their services are probably not worth it for you.