I've got the Cardio (but not the music)... was a toss up with Garmin Forerunner...

believe me I researched the hell out of this. Keep toing and froing. Went for The Spark in the end as it does everything... run, walk, bike, tread, gym, swim, static bike, etc. etc. and concensus was it was quicker picking up GPS.
I could have easily gone for the Garmin though.
Nothing against Fitbit's - I've had a Flex and a HR and enjoyed both. Not tried the Surge though but you can pick up a Spark HR for around £10 less on Amazon.
Been pretty pleased with it so far.

The market is so close though....

here's a guy who has had both....

"Hi dingobot. I own both devices. I used the Surge for over 8 months before switching to the Tomtom Spark Cardio & Music a couple of weeks ago.
First things first - the Fitbit is prone to breaking. I've had it replaced twice in that 8 month time-frame due to the strap cracking/ripping. Because the strap is integrated there's nothing you can do once it breaks except demand a replacement. In fairness to Fitbit their replacement process is one of the easiest I've ever had to deal with, but once I'm out of warranty that won't help if the strap breaks again.
That's the main reason I've switched to the Tomtom.

The Fitbit experience is vastly superior if you're looking for an all-day activity tracker. At least it is until Tomtom decide to implement continuous heart rate tracking. The Tomtom is much better as a device for running - so many more options. And of course since my model has music and the ability to pair with bluetooth headphones I can run without my phone, which I have to admit is weird after 5-6 years of running with a phone! I imagine the advantages would be similar for cycling, though I don't do that myself.

I have to say the overall Fitbit software experience is much better too - the mobile app and website just offer so much more than Tomtom currently do.

So to summarise.
Build Quality - Tomtom
All-day Activity Tracking - Fitbit
Workout/Run/Cycle Tracking - Tomtom
Software - Fitbit

Since you're talking about similar pricing I think you're looking at the Spark without Music? Honestly if it wasn't for the issues with how easily the strap breaks on the Fitbit I'd suggest that model. There's a lot of things that I miss about my Fitbit device, but that's all moot if you can't be sure it'll last more than a few months before breaking!

Lastly - Garmin have just introduced a new watch called the Forerunner 235. It's quite a bit more expensive than either of these two but on paper at least it looks like it has it all over the Surge and Spark. It also looks like a watch not a pip-boy from Fallout! I'm waiting to see how DC Rainmaker reviews it and seeing how quickly Tomtom can roll out updates/enhancements to the Tomtom before I bite the bullet and give up on the Spark."

Hope that helped!

Posted By: Pixelman, Jul 26, 17:25:07