Welcome to the community! Absolutely one of the best things about SmartThings is the high activity and helpfulness levels of these forums. 
As for your questionsâŠ
Version 1 of the SmartThings hub, which is what you got since V2 is not yet available, can do the following integrations:
Basic command set Zwave with some extensions
Zigbee HA 1.2 with some extensions
Some cloud to cloud if both companies cooperate or thereâs an open API
An official IFTTT channel which is useful for many things
Thatâs it. No Bluetooth. No Homekit. No websockets. No local WiFi.
Right now there is no official Echo integration, although thatâs the one that seems most likely to apper in the next few months as we do know that people are working on it.
There is some Sonos integration through the âSmartThings Labsâ route (which essentially means Beta). Not perfect, and a number of features are missing, but a lot of people in the SmartThings community do have Sonos and are using it to some extent.
No integration with Ring Doorbell. There are some community members who have it and like it, it just doesnât integrate.
Roomie Remote does have official SmartThings integration that seems to work quite well. See their forums for more information. One of their company founders also has SmartThings, which Iâm sure helps.
Philips Hues are also in SmartThings Lab status, meaning some things work, not everything. The Tap does not work with SmartThings.
I cant say whether you made the right decision or not, that just depends on your use case.
I personally have SmartThings, have invested minimal money in it, and use it for some convenience cases. It handles my zwave doorlock well for what I need, I have a contact sensor that tells me whether a first aid cabinet was left open and another that tells me when a gate is opened. It also has limited Harmony remote integration which we use a lot at my house. The IFTTT channel gives me awkward but workable voice control of quite a few things. I moved all my lights over to Echo for now.
There are other people who have literally hundreds of devices running on SmartThings, do a lot of custom coding, and are very happy with it.
So it all depends on what you need. If youâre already using Roomie Remote and like it, SmartThings may be the perfect way to add some additional devices, even though you arenât likely to be integrating everything within ST itself.
That doesnât mean ST wonât bring value to your setup: everyoneâs needs and preferences are different. I personally donât use RoomieRemote because I need handsfree options. (Iâm quadriparetic.) But I know a lot of people love it.
Once we get better Echo/ST integration, that will be very nice for my purposes. (Love my Echo.) Other people might not care at all.