Android - Huge app ecosystem, but a non-starter for anyone who doesn't consider it acceptable for mass scale harvesting of personal data by an advertising company. It's a "half open" platform, but the app ecosystem is a clusterfuck of crapware.
The crapware really isn't a problem. No one is forcing you to install crapware on your phone from the app store (undeletable crapware pre-loaded by the carrier and mfgr is another matter). If you're picky about what apps you install, you shouldn't have a problem. It's really no different from Windows that way: there's all kinds of crapware out there, but no one is forcing you to install, say, McAfee or PeopleSoft or some random toolbar on your Windows PC. Just stick to Firefox and MS or LibreOffice and you'll be fine. Now the danger of platforms like this is that you can easily install crapware, and you have to be a bit savvy and not completely naive and trusting that everything out there is OK. With (relative) freedom comes responsibility. So if you're a gullible fool, then you better stick with iOS and Apple iDevices, so that Apple can hold your hand and make sure you don't do anything you're not supposed to.
Unfortunately, you're right about the mass harvesting of personal data part. This (and Apple's approach too) is a consequence of having a non-open platform, where you don't have access to the source code, nor can you easily change the software. Whoever controls the platform can do whatever they want with it. With Google, they mass-harvest personal data. With Apple, they control everything you do. With MS, they give you a shitty, broken UI.