2017 non-Pro 128GB iPad owner here. Whilst I'm considering the 256GB 10.5 Pro, the 2017 iPad is no slouch on any front. Used it daily for banking & budgeting, Apple Music, ebooks (via Kindle app), Netflix, iTunes & Prime video streaming, web browsing, PDF reference at work via OneDrive and light note taking with OneNote and audiobook listening with Audible.
No concerns whatsoever with performance, multitasking works incredibly well, on screen typing with folded back Smart Cover is great. Only reason I'm considering a pro is for stereo speakers, Smart Keyboard cover and pro motion. My old late 2011 MBP has been all but replaced by the 2017 iPad. Will be sharing a laptop with Mrs in the future rather than having a MBA/MBP each.
Upgraded to the 2017 iPad from a 1st gen iPad mini with Retina display. The increase in performance and utility has been astounding. Don't let the lack of an -X suffix on the A9 processor fool you - this is and will remain a seriously capable machine for some time to come with iOS 11.