I love WP, and honestly I'm getting a little bored myself. I scour Twitter and WPC every day hoping for exciting WP8 news. The app announcements are great, and I'm glad to see sales numbers continuing to improve- but I really want the 8.1 update and more OS features. I've played with Android phones and tablets over the last few years (admittedly I've never used a "pure Google experience" device) and it never "clicked" for me. It sounds dumb to say but something about the fonts, layouts, and overall UI was just unappealing to me. I keep peeking over the fence though; I like the idea of being able to customize things a little more and the idea that developers are free to create experiences that are unavailable on iOS or WP8. I always imagined that WP was going to create a middle path between the very restricted but well-designed iOS and the very messy but unrestrained Android. Thus far, I've been very happy with the WP design and UI (except for the Settings menu- what a mess), but I'd like to see them lift some restrictions and enable more experiences.
To the OP I'd say go play around with Android for a while if you're feeling bored. In the $300-$400 range you've got a lot of options (Nexus 5, Moto G, even a gently used Moto X or HTC One). I wouldn't get too caught up in the specs, though. Most reports indicate that the Moto X and Nexus 5 are really fantastic devices even if they do not have the absolute highest-end specs across the board. Go play around, then maybe come back and try a new WP8.1 device this summer and let us all know how you found the switch. Cheers!