...assuming you already have an HRM (but who here doesn't :o) the pricing of the FR230 is pretty appealing compared to the €399 of the FR 630 for essentially the same "useful" features for running in the same form factor. For €/$ 249 you get everything you need for running and then some, VO2Max/Recovery, Steps, Phone Notifications, Access to ConnectIQ.
By the token of "useful" features I already get that from my FR610 ("Finish Time" would be better than "Virtual Partner" though) and I have other nice watches to wear. And I can get (more) advanced recovery info using a free Android app like "Elite HRV". The 235 would at least bring 24/7 HR but without HRV ability and how far is an HRM strap if you really need one?
Decisions, decisions...