Hi Abe,
I have been teaching with Manhattan since before the acquisition, and I can assure you that we operate entirely independently. In terms of quality, you're looking at 4 main elements: books, class curriculum, instructors, and support. Let's take a look:
Books--These are still the top of the industry. Our approach hasn't changed drastically, but we continue to improve our approach, and we've added titles such as Advanced GMAT Quant and The GMAT Roadmap.
Class Curriculum--We've always had a great curriculum centered around real GMAT problems that relate to the topics you work on in our books. This curriculum has only gotten better with time, as we've built on our experience with students around the world.
Instructors--We still only hire the best and brightest. All of our instructors have 99th percentile scores (760 or higher) and 2+ years' teaching experience, and that's just the beginning. I worked on the hiring team for a while, and it's amazing how many people who met those qualifications
still didn't make the cut! We hire fewer than 5% of the candidates who meet our requirements, and then we subject them to intensive training. The goal is to find not just charismatic test geeks, but true professionals with a talent for teaching. That's why we pay $100/hour. We want to attract brilliant, talented people and hang on to them, and that's just what we've continued to do over the five years I've been with the company. Marcus Hedahl in particular is a great example of this--the guy's a physicist
and a philosophy professor, but he's extremely down-to-earth and relatable. He could pretty much rule the world (and he still may), but in the meantime he's teaching for us year after year.
Support--Our Student Services team is still our own, and if you call, you will talk to a real person who can help you with just about anything you need. (They won't take the test for you, though . . . ). We also offer an increasing range of online resources such as IR Interact, with more coming in all the time.
So . . . we're doing great; thanks for asking!

Sorry if I sound like a marketing guy (I'm not), but we're pretty awesome, and sometimes I just have to say so!