There are no inflation rumors, there are inflation facts: Ripple themselves admit to inflation, and try to spin it so it looks like a good thing.
Strictly speaking the supply isn't increasing, as all 100bn XRP have already been created. But only 38bn are in circulation right now (out of which up to 10bn is in the hands of Ripple), so releasing up to 1bn into the wild per month does have an inflationary impact.
1bn is 1% of total XRP supply ever, and that is not a drop in the ocean. It's a sea.
There is a lot going for Ripple, but there is also a lot of potential for market manipulation by Ripple which is built into the distribution model. And it's most certainly not a decentralized coin in the sense most people in the cryptocurrency world mean: Ripple is merely geographically decentralized, not decentralized in the sense BTC is.