Okay, so there are quite a few people with high case numbers. I don't know if it's a trend yet, but the number itself is not as important as how many people there are in front of you. As a rule of thumb though, if you have a number in 40XXX, 50XXX etc. it is considered high and that usually means you won't be current before June, July etc. 2014. Every year the progression of numbers is different, this year for example, it seems to be slower than previous years. People who expected to be current in November 2012 or December 2012 became current in January 2013 or February 2013.
For those of you who are not familiar with this process, your case numbers serve as line order for your case and every month starting in October 2013, State Department will provide the cut-offs for DV 2014 selectees which is the highest case number that can be processed starting the 1st of that month. So for example, if your case is like 2014EU000123XX and the cut-off for January 2014 is 12500 for Europe, that means USCIS will accept your application starting January 1st (or 2nd since 1st is new year!).
http://travel.state.gov/visa/bulletin/bulletin_1360.html
All 2014 diversity visas have to be distributed between October 1st, 2013 and September 30th, 2014. No exceptions. If you don't get an interview until September 30th, you don't get a green card.
Every country has its own quota(
EDIT: this is not accurate, regions have quotas, countries have their own selectee numbers), if the people from your country/region who has lower case numbers than you deplete all the visas before you had a chance to have your interview, you don't get a green card.
You need to make a decision whether you want to do AOS in US, or go back to your country and do CP, because AOS is considerably slower than CP. People who are current in a given month may get their interviews in that month or the following month in Consular Processing; whereas in AOS you wait for an average of 60-90 days after you send your package to USCIS. That means that while you are waiting for your turn, people in your country/region whose case numbers are behind you are getting their visas before you.
If you have a high CN (and also possibly from a country with low number of selectees), it is advisable to do CP.
http://travel.state.gov/visa/immigrants/types/types_5715.html
This link gives some idea about how many people are selected from each country for DV 2013, keep in mind this is the number of selections, the actual issued visas are about half of these numbers. If your country has a selectee number of 50, 100, 150 etc. I'd personally consider it as low (
EDIT: this may not necessarily mean higher risk). If it is in 1000s, it is fine. Remember that each member of a qualifying family gets a visa number. The case numbers are not consecutive, so you don't know exactly how many people are in front of you. And you don't know how many dependents each one has.
In the light of these facts, you need to make the decision for AOS vs. CP. Do not let these facts scare you, (
EDIT)unless you have a high CN, chances are you'll get your interview before September. But you have to make your decision knowing these. Note for SA region: visas in South America may be issued faster so doing AOS may be riskier for those countries.(
/EDIT)
This was some general info for those who are already in US (or about to come to US with a visa) to make the decision about AOS. Of course everybody has their own unique case, if you post your questions, people will try their best to share their experiences and knowledge with you.
Thanks Sm1smom. 
