The biggest effect I've noticed from using it is the "taking the edge off" during a stressful work day. A sublingual dose of a full spectrum CBD oil @ about 15mg CBD content makes a serious difference. If your mind races all day with random thoughts/songs/BS, it also helps to calm that down and increase focus a bit.
For sleep, CBD isolate is the way to go. Isolate is 99.7% or so pure CBD, so none of the terpenes, etc. from a full spectrum oil, but all of the CBD. 60-100mg sublingually works wonders. Even on the cheaper end, you're still looking at a couple bucks a day, so it isn't the cheapest sleep aid out there.
That said, there is a big difference from brand to brand, at least for me. A 60mg dose of powdered CBD Isolate from CBDistillery will put me right to sleep, but the same dose of isolate from Bluebird Botanicals will keep me awake and semi-wired all night. Same goes for the oils - Bluebird, Charlotte's Web, and Lazarus Naturals all work well for the stress reduction, but others don't, at least for me.
You kind of have to experiment with the brands and dosages to find what works for you, but the effects are pretty noticeable once you find the right brand/dosage combination for your particular needs.