I own Texas Photo Workshops and have worked as a photographer for over 30 years shooting for most of the major magazines, including NGS, Life, Smithsonian, etc. I have always taken at least one workshop every year myself. I was the Photo Editor for Texas Highways Magazine when I decided to leave and start TPW. Without trying to sell you on "my product". Allow me to give you some workshop selection advice that has served me well through the years.
The very first thing you want to consider when choosing a workshop/class is "who is teaching the class". What are their creds? They are going to help shape your photographic eye. You don't want bad or mediocre photographers training you to see they way they do. You want photographers that are tried and true. With the exceptions of a few teachers in college, I recommend staying away from colleges. The teaching talent will not help you for the most part. Again there are a few exceptions out there and again look at their working creds, not academic creds!
Now online classes can be great, again depending on the instructor. Online studies require a lot of self discipline, but if you do the work, ask lots of questions and keep trying in the face of failure you will get more than your moneys worth no matter what the cost! What you miss from the in-person workshop is the personal instructor "one on one" time that is huge and the synergy that comes from the other students. If you can afford taking workshops from A-List photographers in person, that is better than online. Now better than both online and in-person workshops is buying "one on one" time to mentor with very accomplish shooters. It's costly (I charge $900 per day) but well worth the investment. Your education is worth more than all the equipment shooters are buying these days. I'll put my money on an accomplished shooter with a box and a pinhole over any amateur with a 7D any day.
Ok, I like my company the best,
www.texasphotoworkshops.com, but other good ones are Picture Perfect School of Photography, Jay Dickman's Firstlight Workshops (NGS considers Jay to be one of their "Photographic Experts" and he has been one of my mentors through the years) and Dave Black,
Dave Black Photography - Sports Photography Worldwide. Good Luck!