Yes, I've done online dating and have had more than one long-term relationship.
It's not about how you meet but whom you meet that counts!
Online dating is just another (tool) for people to meet other people.
Much like a fork can be used to eat a garden salad or a slice of double fudge cake. The only difference is an obese person never blames their (fork) for their weight gain while people who have a bad dating experience online often will blame the online dating industry!
Each of us gets to (choose) our own friends, lovers, and spouse.
If someone is experience having one bad relationship after another it's probably time they re-examine their "mate selection criteria".
The only thing for sure all of your relationships have in common is YOU. :)
Always use good commonsense when meeting stranger online and offline. Be selective about which site you decide to join. They're not all "equal". It pays to do some research.
There are also (niche online sites) which may cater to an important trait one desires in mate; (race, religion, nationality, political affiliation, income, sexual orientation, and so on.)
Lastly there is (Meetup.com) which is not an online dating site but rather a site that has thousands of groups of people who meet once per month or more who share a particular hobby or interest.
Groups include book clubs, wine tasting, yoga/meditation, theatre goers, hiking, bicycling, writers, singles mixers, dancing...ect.
This allows one to get to know new people gradually in meetings.