Stop deceiving yourself. Even with WP8.1 (and it is no longer in BETA), resuming is still happening on slower devices. Face it. Windows Phone OS is not as slick as we are told. It requires good hardware to make it shine, just like Android and iOS or any other OSes. I'm seeing lots of resuming on the old 1020 than the 1520.
And IMO, Android is still better in handling app switching. When I tap on the notifications on the Android, apps launch / switches immediately. On the other hand, Windows Phone animates like crazy whenever I tap on an incoming toast. Opening Whatsapp on 1020 is darn slow. App issues? Consumers don't care. If it is slow, they switch. Simple as that.
I agree. No matter the theoretical superiority of how WP handles opening apps and app switching, Android outshines it by a long shot in real world performance. My 920 that has almost nothing on it takes forever to open apps. And no, there's nothing wrong with it. I've had 2 920's and other miscellaneous WPs, and they're all the same. Even now, when I open Cortana on my 920, I wait 3 seconds while it says "Getting things ready...". I can close it and reopen it 1/2 second later, same thing. I unpinned Cortana's live tile, no difference.
I just testing opening apps, comparing my 920 with WP8.1 and my Verizon Moto G with KitKat 4.4.2. (I use a Nexus 5 as my daily driver but I know that wouldn't be a fair comparison to the 920.) I tested eBay, Reddit (Baconit on WP), and Tapatalk. I cleared the recent app list on both so they were both opening the apps cold. The Moto G won every single one. And, when I closed them and reopened them, there was no comparison. The Moto G reopened them instantly, but the 920 had a lot of animation before reopening them. Now, I don't know if animation is always part of opening apps and the app was waiting on the animation, but either way it takes a long time until it's ready to go.
In short, the app switching system in WP needs a lot of work to get anywhere close to what it's up against.