The ROI calculators show a first year 7% ROI (of course, this will increase as electricity prices increase).
Although not DIY tends to basically double the price, you realistically have a 2-3 year payboack, or an ROI of 33-50%.
I have a 5YO toy 500W DIY system, currently, and it has already more than paid for itself, without bothering to get a second meter to take advantage of generation in excess of consumption (yeah, you want to know why the utilities suddenly and "inexplicably" wanted to move to smartmeters? Unlike the old analog meters, they won't simply spin backward if you make more than you use, so FUCK YOU, consumer-with-solar).
The Brookings institute clearly analyzed this from the POV of a monopolistic unitility company, because for end-users, a home solar array practically counts as a no-brainer with current prices, assuming you can afford to sink a few grand into it up-front.