I only use Fodors and TA for my references, but I am generally pleased with the information I receive. I do try to read a number of reviews and not base my decisions on one or two. I also read the profile and other posts of the reviewers to help evaluate their comments. Sorry, I don't do smart phone apps.

For example, I have read a number of your trip reports and think you provide very balanced evaluations and excellent advice.

I use Fodors, TA and Yelp. Usually I recognize the Fodor's contributors so I value their advice. TA is very helpful especially when I'm looking for a restaurant within walking distance of my hotel or another site. Yelp also helps me identify possible places but the opinions are often all over the place.

I use TA to vet hotels. I don't look at the ranking, just the rating and the actual text of the posts. I find the Traveler's Photos to be very useful.

I use Yelp to look for restaurants, and have a general rule that under 3-1/2 stars is a no-go, 3-1/2 is "fine" and 4+ is good.

And of course Fodor's forums.

I use TA for hotels. I don't find TA or Yelp that reliable for restaurants. I've eaten at some really bad restaurants that were in the top rankings on TA or 4+ stars on Yelp. I think sometimes it comes down to the lowest common denominator. For restaurants I use the Chowhound forum.

I use TA and Fodors for hotels but not for restaurants as the results for my local area are really terrible.The worst chain restaurants are at the top, awful si I trust trust those.
I use Urban Spoon, Chowhound and Yelp for dining recs.
Zagats too but now it's through Google? Not sure it they made the switch yet.

I used Zagat too (always subtracting 3 points from every restaurant's points, because I think that's how much they're inflated on average), but the app is no more since the Google buyout. I don't know what's going to happen now.

Especially like Chowhound, in additon to Zagat, Urban Spoon, Yelp, TA and the others. Best to cross check if you really want to know about a place - and also - read reviews from the local newspapers.

I think they all offer something - especially if you read a number of the individual reviews.

With anything, it's wise to read with discernment.

That being said, I've generally done best with Chowhound, at least for food. Fodor's guidebook suggestions for food and lodging can be good, while Frommer's guidebook suggestions seem to be a little more hit-and-miss. Frommer's definitely seems to have problems with keeping reviews up-to-date.

I've found Zagat less good for food than Chowhound, though still useful to an extent.

I've historically been very suspicious of Tripadvisor and Yelp given their significant problems with phony raves and gripes, and am much more suspicious of both since I found out businesses can pay a fee to have bad reviews removed from these sites. I rank these way down on the trust meter.

I use the Yelp app on my iPhone when I'm traveling and want to find something good nearby. I've had great luck with it in San Diego and Chicago (the two main trips I've taken since getting my phone). Like anything else, you have to filter the reviews - I tend to ignore ones that read along the lines of "service sucks" or "omg pancakes!!!" Past that, I look for reviews from people who focus on the same things I would. I don't care much about cocktails, for example, so I ignore reviews that only talk about the bar menu. And I try to filter out any that sound way too much like a restaurant manager wrote them.

I find the pictures people post about restaurants on yelp to be helpful. I don't put much stock in the words, but a picture paints a pretty good idea of what to expect.

I use the Yelp app as well when I am travelling - esspecially for business. When travelling for pleasure, I usually have time to research some restaurants ahead of time, but when travelling for work, not so much. The Yelp app helps me find decent local places quickly.

At least for my hometown, most of the people who respond to TA are tourists who seem to either go to restaurants that are known or convenient and about half of Yelp do not know what they are talking about especially when it comes to ethnic food.