Some random comments...
I actually use the Wink Hub to directly control my Caseta switches via ST-IFTTT.
All of these consumer-grade HA products have to be considered a hobby. Given the hundreds (probably thousands) of hours I spend playing with this, I couldn't possibly justify it based upon ROI. For instance, re: pool control, I have my pool integrated to ST, but I won't put a mission-critical item like the pump control under ST; yes for pool lights, waterfall, etc but the pump is run by the control system timer.
Here's a face-palm. A friend of mine is building a new house and his builder adamantly insisted on Wink for a security system. OMG! I have my 25 year old Honeywell Vista 20P bridged to ST, and there are a lot of convenience features from that, but no way would I trust any current system - probably never any wireless system - to home security. Jeez, just throw a few hundred feet of twisted pair in the attic connected to $1.50 contact switches and be done! If you want to get really upscale, buy a $50 panel off eBay.
My A/C came vanilla with a cheap Wi-Fi Honeywell thermostat and, search as I might, I can't find a reason to buy a Nest or Ecobee. My thermostat control is really basic, but it's all I need: When everyone leaves, I raise the temp, when anyone returns, it goes back to whatever the pre-programmed schedule should be.
Speaking of presence detection, this is a real thorn-in-my-side. I don't like fobs, so I'm trying to get effective presence via Android phone. The weak link is the phone dropping off and false negatives for presence. My method now is to use Tasker and its various ways of detecting presence (some mix'n match of Wi-Fi, cell tower, GPS, etc.). With Tasker, I can play with algorithms to overcome a false report of departure. Results so far are not great.
Smart bulb (e.g. Links) vs. Switch: Smart bulbs are just frustrating. I still have a few, but I much prefer a $4 LED attached to a switch. No confusion, high reliability. I think the ubiquitous GE Links have turned off a number of early adopters of HA.
In wall relays: they seem to be pretty expensive (maybe not in terms of list price, but they don't ever go on sale compared to most of my "Decora" paddle switches which I've purchased for $10-16). So I've never used them, but I really prefer the old style switch - a lot easier just to flip it up or down.