As always, I chose the Omni based on Tripadvisor reviews. That's why I feel it's important to write reviews - as a way of giving back to other reviewers and the Tripadvisor website for their contributions to making my family trips the best that I can plan.
The Omni is a great location for downtown Los Angeles touring. It is two blocks from the Music Center, where we attended a play, close to Koreatown, where we shopped for great produce at one of the huge markets, close to Chinatown where we dined on dim sum, close to our friends and family in the increasingly upscale Silverlake district, and close to many "authentic" Mexican taquerias. It is a beautiful hotel that was very busy on the weekend that we stayed - a testament to its popularity, I believe. The rooms were spacious and immaculate, the bedding delightful, and the bathroom well appointed with very good water pressure.
Downsides: telephone buttons didn't work well, difficult to get the concierge and valet parking staff, movie rental system didn't work consistently, in-house restaurant, Grand Cafe, had terrible service and so-so food (but they deducted the cost of the entree that was not properly served, thank you!).
Not insurmountable downsides, but perhaps a bit disappointing, given the pricetag, which is on the higher end.