People here are well aware of the pluses and minuses of Nexus devices. There are those that run through every Nexus devices, and some specific to Nexus 4. For me personally the phone itself is attractive enough, does everything I want, and I find interesting new apps on a regular basis (and they're always compatible with Nexus 4 first). I can "upgrade" to any phone I want @AT&T for $99 but I haven't bothered.
There is no competition between HSPA and LTE as to speed, but you end up paying for the GB you use, and that can be seen as glass half-full or half-empty. I know it first hand because I have 3 LTE devices and 2 HSPA devices under a shared data plan I pay for. If you are using a lot of data on the go, then LTE is def. desirable although HSPA is not a slouch. If you have Wi-Fi access in more places than you care to, then you might as well save your mileage and use Wi-Fi - and in that scenario LTE becomes less important.