I totally disagree with your there. I've always been a tomtom user and was pretty set on buying the 6000, but after trying them both out in the shop, the 3598 seemed miles better to me. Tomtom had removed loads of features that were standard even on my old XL Live, whereas the Garmin had everything my tomtom had, plus a load more. The speed camera locations were far better as well, and I found the live traffic far better than my tomtom, which would invariably send me off motorways and down minor roads which were just as congested.
I guess the 6000 may have been improved with updates - I tried it a couple of months after release, but for me it was inferior to the Garmin in every way.
As I said, Tomtom have made massive improvements in the software since launch, and luckily I demo'd a GO6000 5 weeks ago on the latest software version, which added voice control, and a raft of the originally missing features, just about all that is missing now is the ability to put third party POIs on it.
Things the Tomtom impressed me with
1. Search for my parents Spanish townhouse address, I simply hit search and partially spelt their road name (I was unsure of the correct spelling) and it searched all maps pretty much instantly and offered their road as the number 1 suggestion. The Garmin needed me to go through the usual steps of inputting country, then town, then street name. (This was all done standing in the shop in the UK), in fact I couldn't find the address at all until I tried the tomtom and realised I had mispelt the last vowel in their street name, which Tomtom got me around because it's live search picked up the address before I got to the end of the word.
2. The POI search for some random shops and places was evidently more successful on the Tomtom, and the 'search online' furthered that gap
3. The display graphics are much more appealing, it actually looks 'modern'
4. HD Traffic for life is a nice addition
5. The Text to speech voice (not the default btw) is very natural sounding and even attempts passably with foreign names.
After owning it for a month or two, I am still impressed, it's been very accurate, the traffic has picked up way more hot spots then I thought it would, the voice control is amazing (but you need to be patient)..
However, for fairness, the following are the negatives I've found
1. Updates to maps/main software is done via a PC and takes an age (even on a 160mbit connection)
2. The full lane assist (like all lane assists) can lead to confusion on complex junctions, especially if you where not paying attention prior to it bringing up the large lane assist animation, which hides the main map and your actual position, this caused a minor detour on our 2200 mile euro trip until I found out how to switch it off.
3. Voice control struggles with cabin noise present (as you'd expect) and you need to be patient with it..
4. I found the roadworks where 24 hours out of date, so ones that ended that day would still appear into the following day.
5. Like all PND's it's a bit laggy at times and you wonder why you can't get a super quick processor in these things (the Garmin was similarly laggy).
Traffic HD has been almost flawless, it picks up B-road rush hour jams, it's never steered me off-course incorrectly in 4000 miles of use and I like how roadworks are handled. Speed cams are OK, but being honest, they are slow to remove roadwork average camera's etc, although they picked up 100% of known speed cams around me and my parents in Spain, so I can't complain too much.