I don't think the Entune systems are "bad" per se. I just think they are an overpriced option that is significantly inferior to aftermarket choices. In my case, my 4Runner came with the non-nav unit, so I'm using an external Garmin (2597LMT model) instead that is mounted in the front cup holder. My wife's Rav4, however, has the Entune Nav system.
In my FJ Cruiser, I removed the factory CD/Radio and replaced it with a Kenwood head unit with integrated Garmin nav system. It's half the price of the factory system, and is far superior (in my opinion) to the factory system.
I don't think too many people will argue that Garmin is the top dog in the nav pack right now. The downside, however, to the setup I'm using is that it's an external unit (read: Please break my window and steal me....), and you can only have your phone connected via Bluetooth to either the factory Entune head unit or the Garmin nav unit. It sucks because Entune won't let garmin units connect via Bluetooth, so you have to choose one or the other. In reality, you need to be connected to both.
As I mentioned in another thread, I wish I could've "opted out" of a factory head unit altogether and dropped the price by $500.00 on my 4Runner. I'd have gladly spent $1200 on a Kenwood unit with all the needed bells and whistles, and would have a superior unit to the Entune system.
Now with all that said, I have no intention of swapping out my Entune head unit any time soon. It plays music (via radio, iPod, or usb), Gives me a weather and traffic map, and lets me safely talk on the speakerphone while driving....so it gets the job done. The Garmin unit is a far better nav system than the Entune, and is constantly updated with current map info. PLUS, I can plan trips on my computer via "Basecamp", and then load them into the nav unit in advance. If I could just integrate the Entune and Garmin units via Bluetooth, I think it would be perfect.