As stated by others, the Extended Validation (EV) certificate is structurally similar to standard Domain Validation (DV) certificate. The difference is not about securing the pipe between the browser and the site, but rather the level of diligence done by the Certificate Issuer in the process of granting a certificate.
Certificates are like passports. Saying that the certificates are the same is like saying two passports from two different countries have the same security features. It means they have the same protection against being forged. It doesn't however tell anything about whether the certificate/passport was issued to the right person. That's the difference between Domain and Extended validation certificates.
For example, I don't know the actual criteria used, but 'Domain Validated' means just that. Hey, we contacted you at an e-mail address with this domain and you're from that company, so here's the certificate that you paid for. Validated by domain.
By comparison, the extended validation would mean that maybe the certificate issuer contacted the legal department of the company that owns the domain requesting the certificate to verify that the requester is authorized to get a certificate for that domain. That way they can verify that just because you work at the company, you're not going to be able to get a certificate with the company's domain issued to you.
So, as others have stated, does that mean your users will know the difference and be paranoid enough about the information they're giving you to care? You may not know. If they're supposed to give financial information, I'd spring for the extra $$$. If not, it probably doesn't matter as much.