I receive the questions "Do you know if any honest agency" or "Where do I find a real Russian woman" at least 5 times each day. Let me post my suggestions here, so everyone can view them:

Most of the time, which agency you go through does not matter. What matters is how much you know about scams. You will find both real ladies and scammers almost everywhere. It is your responsibility to educate yourself about all types of scams so you can use your judgment to determine who is worth your attention and who is not.

Here is my suggested plan of action:
1. Read all you can about Russian and Nigerian dating scams online. Know all types of scammers (yes, there is more than one). Find out the most common scam tricks. Become an active member of at least 1 anti-scam forum and at least 1 forum where married Russian-American or Russian-[insert your nationality here] couples discuss post-marriage and immigration issues. Be familiar with all major black lists. Instead of just browsing through their pictures, read the actual repost and make observations about scammers' ways to ask for money. 
2. Once you are sick of reading scam reports, start writing to ladies. Start by searching online for negative reports about largest agencies in the market (by then you will know them all by name)  and get to know their dirty tricks.
4. Decide (based on those reports) which one of them is the least of all evils.
4. Browse their database, and decide on 10-15 girls who do not look familiar (if they look familiar, you might have seen them on the black lists). And remember, the cutest girls get the most letters from other guys. Write introductory letters to the girls you like, and hopefully a few will respond.
5. Start correspondence and tell them that it is going to be several months before you meet, and that YOU will travel to their hometown to meet for the first time. No inviting them over to your country or on "vacations" to other countries! 
6. Find out their full names as soon as you can and try to verify their information through my agency or any other agency that you think looks trustworthy (google them first to see if there are any negative reports about them). Also you can use flower delivery agencies (that are not associated with any dating sites) to send flowers and ask for pictures of the recipient.
7. Watch for warning signs. If the relationship start to remind you a scam - back out or get confirmation of girl's stories somehow. Do not write the red flags on "cultural differences". When in doubt - ask people from the forums that you are active on (and actually listen to their suggestions). Try to narrow your choice down to 1-2 ladies. Then start planning your first visit. Do not lie to ladies about them being "the only one" if it is not true. If you expect them to be honest with you - be honest with them. 
8. When you are ready to visit, arrange your accommodations through a third party (do not use companies that the girl or the agency suggest). Do your due diligence research before committing to any travel or accomodation service.
9. Take it from there.

If you:
- Do not have money to travel to Russia
- Do not have time to travel to Russia
- Think my suggestions are too much work for you...

Then I do not know what to tell you. Maybe international dating is not the best choice for you.

My suggestions are only suggestions. I am sure there are other ways to go, but it is the one that I recommend.