I'd actually think the 'minus VAT' price makes more sense, since it's a tax issue and not a 'list price' issue. In Erica's case, if they were shipping direct to a EU client, that client would have to factor their VAT on an overall basis against all their EU-purchased devices, but not something from the US or Canada unless it was purchased thru an EU retailer. Likewise, if someone walks into a shop in the USA to make a purchase, local taxes will apply, so an Erica module here would have a lower initial price, but the addition of sales tax (state and local, as a rule) changes that price differently. And, of course, you have the whole issue of import duty, etc etc. Gets messy and confusional...so going with a manufacturer's 'base price' seems right to me, with the onus being on the customer in question to factor their taxation situation as per where they are and how things get purchased.
So if a manufacturer posts a 'with VAT' price, actually those who don't have to deal with VAT come out ahead. Again, it's a 'worst-case' price in which the 'surprise' is the lower cash outlay, instead of the 'best-case' price that isn't realistic for the majority of users who wind up with sticker-shock on ordering.