Speed warnings are a setting in your preferences. I have no idea what a gatso camera is and have never seen a warning for it so I'm not sure what to tell you there ... I've had the app since it FIRST arrived in the app store and I didn't even know about that feature.
On the 3GS, the TomTom app was an absolute HOG and after a few iOS updates it became relatively unusable for a while -- would tell you to 'Turn Left' when you were already past the street by as much as 200 yards -- only because the processor wasn't fast enough to deal with the data. And there was NO WAY you could use the 'Play Music from your iPod thru TomTom while driving' bit... Just took the phone RIGHT down.
Now, however, with the iP4 I can play music thru the TomTom app (control it there too -- the advantage over just Multitasking the two apps is that TomTom will 'dim' your music momentarily to give you voice nav instructions) and rarely if ever miss a turn (only if you're starting up the app while driving [*tsk*, *tsk* - do it all the time] and the GPS might not fully render your route first.
I think if the app is $35.00 now, that's really worth it -- I have *not* tried any of the free ones.
A couple of features that come with (or are available for) TomTom are pretty cool:
1) Advance Planning--you can pre-set a trip for a specific time / day (like if you know you're going to be heading to a Dr's appointment tomorrow at 3, but you'll be leaving from work -- you are at home right now but you want to see how long it might take or check out the route / instructions -- or even better, somebody who can't figure out how to use the phone will be doing the drive and you want to set it up. For them) just plan the route and you can add it to an iPhone calendar event that pops up at the right time, click on the link and you're off -- even if you're not where you thought you'd be when it was time to go. [problem: doesn't allow you to set up multi-point trips REALLY -- you can set up multiple single-destination trips, but traveling via (what used to be known as) 'waypoints' so that you can plan a while trip with stops here and there isn't supported. Hopefully that will change.]
2) LOTS of different voices and languages (Dutch, French, Thai, Japanese, a ton of them it seems) -- it's really quite useful if you speak a second language from the other people in the car -- I've found that I can listen to the GPS speak to me in French, (I only took 5 years of it and can't REALLY speak it any more, but I understand enough to be fluent in the small subset of phrases the GPS needs to use) BUT since it's in another language, for whatever reason it doesn't interrupt my passengers' conversations at all -- whereas the English voice nav DOES stop everyone from talking.
3) Find Alternate Route -- if you know THAT way is screwed this morning, just re-route before you even get out of the driveway. Can route around unexpected roadblocks [though that feature isn't thought out so well -- that, or I just don't know how to use it right] or minimize delays or avoid specific parts of a route, etc.
4) TomTom Traffic -- THIS has to be the kicker. Though it COULD work better at times, it really seems to work VERY well MOST of the time. TTT checks in with some service [no idea WHAT service or how] and will dynamically [yep, on-the-fly] change your route if an accident happens up ahead. It's $20 a year for the additional service but it's practically worth the price of the whole dang phone. [caveat: when it DOESN'T work and you've gotten used to it working -- well that is truly frustrating. There are several problems I've had with the traffic add-on ... But now that I'm beginning to understand what it gets WRONG generally I'm starting to learn how to deal. For instance, in Dallas right now we've got a whole portion of highway shut down (Woodall Rogers) for part of the day. Because Dallas sucks and they don't update road / highway closures with the appropriate authorities / agencies, TomTom Traffic has no idea -- and says to itself 'wooooo-hoooo! That ultra FAST way to Rob's work is totes EMPTY, dude! Sure it's 2 miles outta your way, but seeing as how all the roads around it are SCREWED, it's your best and fastest alternative!" and it will therefore not only route you to a closed highway, but much worse, route you into the belly of the beast of traffic--all of which is THERE because that highway is closed in the first place. And what's worse on top of THAT is that it will have completely ignored a perfectly good slightly slower route to go in that direction at all costs because it believes it can save you TIME in doing so. At the end of the day, this has made me want to go to TomTom Headquarters with an anonymous gift of about 50 pounds of rotting shredded carné asada at least twice -- but in GENERAL the good outweighs the bad]
WHEW! that was a LOT of typing for this little iPhone keypad. Hope it helps!
-Rob 'T.M.I.' Norton