Thinking of jumping ISPs to SNAP, but I'm inherently lazy, so if I've misunderstood something I'd be keen to know.

My Current Status
I'm currently stuck in ADSL2 land, and I run naked DSL with an on account phone discount. I'm well outside any contract minimum terms for both the phone and the DSL. My current data usage is just over 200 GB/Month (and on a gradual rise). This has me paying ~115 dollars/month for internet. I currently also run an a couple of services for myself (Client -> Site VPN, Personal Websites) using a dynamic DNS service to find them from outside.

Why would I change?

Mostly money: For the same price on snap I can get 300GB of data, which is what I use, and take a big chunk out of my usage with the unmetered period in the 1am-7am gap. (I'm looking at steam+humblebundle.com as the big offenders here) so will probably allow for growth. The kicker comes with wanting a static IP: I am looking at setting up a site-site ipsec tunnel and by all accounts everything gets easier with a static IP. The only way I can see to get this on vodafone is a $23/month addon that includes a lot of other stuff I don't care about. Whereas snap says they'll do it for $5.

All of this has me paying approx $115 per month with the possibility of $138 if I get that static IP, where as on snap I can do it for $100. With the possible bonus of being able to move my mobile phone somewhere else as well.

I do play online games, so latency is also an important factor to me, and according to truenet.co.nz snap has ~10-20 ms edge to the US over vodafone so that would be nice.

What has annoyed me

Vodafone seems to have no customer loyalty system: Currently advertised is a deal that would knock $40/month off the price of the connection (free double your data if you sign up for 12 months) but when I spoke to a customer rep in store they advised that I was ineligible for this as I'm an existing customer, even though I'm well outside my existing contract. It seems weird to me that VF (as a corporation) would go to so much effort to get customers, but put in so little effort to keep them.

Why I'm telling you all this

As I said at the start: I'm lazy and would prefer not to have to go through all the mess of switching, but at $40/month it's an easy bet. That said getting the terms and gotchas of telecom agreements are always fun, so I figured I'd ask and see if anyone knows of a better way (or a better deal than the snap one) I'd love to hear.

Also any gotchas in terms of being charged for a month by both ISPs/ getting DCed from one before the other connects you up would be good to know too.