Just got my Echo and wanted to get into home automation. SmartThings appears to be the way to go, now I just need to get some hardware. At first glance the kit seems to be the way to go. However it seems like I can save a few buck if I get the SmartThings hub and go third party for the sensors and get them from Amazon. Any thoughts on suggestions if the kit is worth it? Or parting it out is the way to go?
Depends on the sensors you are considering. I have to admit, the ST sensors are actually high quality, not just higher priced. Makes the decision harder. Wish I could help more. Dive in, its a lot of fun.
I can at least vouch for the ST multi’s (have 5-6 of the new ones). They are very versatile. Haven’t used the other newer products.
I too think that SmartThings sensors are overpriced. I bought all of my devices separately, mostly from Amazon. Saving 10 - 15 bucks per device does add up when you have a few dozen of them. 
It will depend on what you are looking for in a sensor. If you just need an open/close sensor I suggest you buy something from Amazon. I like the Smartthings multisensors because they also tell temperature, acceleration and rotation. Also, the cheaper sensors are often not able to report their battery level.
The ST sensors are way overpriced, I got a kit initially, but i’ve bought almost all of the my sensors somewhere else. the PEQ sensors from BestBuy when they were 20 bucks were a great deal, and Monoprice Z-wave sensors were a good deal as well.
I have a few Multisensors, but found i’ve replaced almost all of them with PEQ open/close sensors. I do like the 1st gen Motion sensors from ST because I could plug them in
The hub is cheap, the service fee is cheap, the direct-sold sensors are not, and it’s an open system. Seems fair to me. Maybe Revolv or Wink is a better deal.
The ST multisensor (acceleration?, orientation, temperature, contact) indeed seems to be high-quality and I haven’t seen its cheaper equivalent elsewhere. The battery life and functionality is incredible, and it compares well.
I’m not entirely sure what sensors/devices I’ll end up needing but I’m thinking I could find a use for all the ones that come in the kit. I know I’ll end up getting a few wall switches which don’t come in the kit anyway. I’ve got a promo code to use on the kit, so even parting it out (without any super deals) it only looks like a $10-$15 dollar difference total (to purchase the ST hub plus similar sensors/plugs). So sounds like the kit may be worth it for the introduction, especially when I’m still figuring out my layout.
Just get a hub and look for devices on ebay for sellers that are giving up on ST ever working right.
Thats where I get my contacts and pirs.