Sorry about the late reply.
Yes you can use MAXCDN and CloufFlare at the same time.
I'd suggest using MAXCDN for static content.

All I know is my google income is 8 times+ what it was, the traffic on my site has more than doubled. Was it worth it? It paid for itself in less than 2 months. The first month I only notice a slight increase. The second month my google income doubled. By the 3rd month the goggle income went up x4 and the traffic was double.

After being used to NuSEO, moving over to vbSEO was quite a downgrade in functionality. While NuSEO is 4 years old and was coded in only a few months its still a better product in terms of functionality. I do think that vbSEO is a good product, but the development seems slow and the product behind the times. 3.6 was a nice update, but it was the only nice update in years. 3.3 was released in 2009. Although some new features are modern, many features are still missing. vbSEO only optimizes vbulletin, but not vbulletin addons like photoposts, LDM, etc. I wonder how many vbSEO customers only run vbulletin, but no addons? I would expect, not many.

Unfortunately vbSEO does not have a function to just keep default urls (Google indexes those just fine and after getting top rankings for many years Im not interested in changing that), so unfortunately Im not using my vbSEO license.
Support at vbSEO is great. Any question you have about SEO will receive a thoughtful answer.

I was already using MaxCDN and with the digitalpoint coupon 1TB is $29 which is a very good deal. But after a year of use, it turned out that MaxCDN was slowing my site down a lot. So after negotiations with my host, I got the bandwidth price down and removed MaxCDN. Its a plus that vbSEO has maxCDN integration if your site caters an audience that is covered by MAXCDN its faster gateways. My audience is worldwide and their European servers are slow, so MaxCDN does not work for me.

I made a huge mistake in going with vbSEO. I have looked at the output and made a logical error that the sum of the parts is greater than the whole ... big mistake. My traffic is 1/2 of what is was, I'm having huge and incessant htaccess and read-write errors, the way the htaccess files were developed they "unlocked" my parked domains so 25,000 links were cached by these domains and my google income is 25% of what it was 2 months ago.

A typical answer I get on vbSEO is a hard-sell and illogical approachs. More on that later, I'll login when I'm not remote and will link to some of my discussions on the site.

Wow.

In all honesty SEO seems like a myth, I believe having a faster host and efficient host. As well as a good theme template and content (*Most Important factor*) is the key.

Buying expensive software may also help but I doubt it if you don't have the above three factors you will succeed.