Hello mate, welcome to ECF.
Congratulations on your decision to vape rather than smoke. There's lots to enjoy and even more to learn.
Mate I'll help you with your questions as best I can. I started vaping a year ago and my first kit was also from V2.
You'll hear both good and bad things about V2's
product, but I for one love the technology that it's based on.
You'll also hear some good but mostly bad things about V2 as a company, as they seem to be looked down upon here and I believe that it mostly has to do with their marketing claims and exorbitant prices.
The ecig you have purchased is based on a common model called the KR808D-1 (KR8 or 808 for short). The KR808D-1's have a standard threading on the cartomizers and battery ends and all other KR808D-1 parts from every vendor are supposed to fit, albeit sometimes they don't fit as well as they should but that's rare.
There are some other companies like Smokeless Image with their Volt branded ecig and Bloog with their Maxxfusion that also base their offering on the 808 model and if you were to purchase batteries or cartomizers from them you'll find they'll fit and especially in the case of the Volt, they'll be cheaper, but that's all part of the learning experience. Many people pay alot more money to start vaping than we did and ended up with substandard products.
I found the V2 cartos to be hit and miss alot of the time. Some were great and lasted ages, some were fairly tasteless and didn't last, but that was a year ago. I got into refilling cartos fairly quickly which is very very easy and there's many methods (youtube refill cartomizer). Popping the cap off and filling it is the simplest and most hassle free I've found.
You can refill carts until they are burned out. Over time you'll get used to noticing when the flavour drops off. That's when it's time to refill. If you keep vaping you notice a burnt taste, that's the filler inside the carto burning and that's when a carto goes in the bin. You can of course clean them out before they are burnt if you've refilled them a few times and the performance is not where it should be, carto's, even though they are stated that they can be refilled up to 5 times on the V2 site can last much much longer of properly cared for.
As I said, I started on 808's. I rapidly moved onto other products like eGo's, 510's, and mods, but I came back to the 808 and I'm very happy with how it performs. Of course knowing nothing about your vaping style I can't presume to know what you'll be happy with in the future, but I will recommend getting a pcc charging case and at least 3 batteries if you're at least a moderate vaper. PCC's can be purchased from many vendors, the cheapest I've found are litecigusa and cigeasy.
Sorry for the blog post, I am well versed in all things 808 and have way too much to share. It's a good unit so stick with it for the time being. and if there's anything I can help with, just ask.
Cheers mate.