Router advice needed.

We're on Telstra/Vodafone cable in Wellington. For a *really* long time I was happily using a venerable Linksys WRT54GL with DDWRT. Things change and I've now ended up with a free Netcomm NF5, which has thoroughly underwhelmed me. There was a long rant here about all the ways it has disappointed and frustrated me, but deleted in the the interests of everyone reading this. Essentially its wireless is slow and unreliable, with poor range (compared to the rock-solid, although slower rated Linksys). It's recently added random resets and dropping internet connections to its repertoire, so it's got to go.

I've read on Geekzone and elsewhere about the benefits of 5GHz and am definitely looking at a dual band router, although 2.4GHz doesn't seem to be too congested around here.

But I do have some other queries I'm hoping for some help with:

- My main notebook's wifi card is an Intel Dual Band Wireless-N 7260. According to Intel, this is rated up to 300Mbps. In real world applications, would an N600/750/900 router deliver better performance than an otherwise similarly specced N300 router, even if both only connect to a 300Mbps notebook? At most, there would only be 2-3 devices using the wifi at the same time.

- Similarly, am I going to get any real world benefits from getting an AC-class router, when the main notebook it is connecting to is only N? My phone has AC-wifi, but I don't really care what speeds it can connect at. I'm sure I've read somewhere that the AC standard includes some provision for beamforming that boosts something (signal? performance?), but is this backward compatible or something that only works with other AC products?

I don't really think I can justify a really top-of-the-line router. The only really data-intensive thing I do is stream recorded Freeview from a NAS to my notebook. There are a couple of TP-links on PBTech that seem to offer a good amount of bang-for-buck. A WDR4300 N750 for $130-ish (that has the added bonus of DDWRT compatibility, and the online reviews seem okay) and an C5 AC1200 for $155.