I was told to avoid registering and hosting at the same company. What do you think about that?

Sounds like good advice to me.

Please elaborate, thanks :)

Well for a start, using the same company will make it much harder to move. Often the price shoots up after a year too. And then there is the risk of somebody getting access, it is easier usually to hack a website than a registrar so a cracker or their could get access to your domain through a security flaw in your website. Also, companies are usually either better at domain management or hosting rather than both, I have huge respect for good support teams like Krystal Hosting have,which is easier when they are focused.

I'm not saying don't use the same company, but I always tend to prefer them separate.

I understood question:

"I was told to avoid registering and hosting at the same company. What do you think about that?"

as

"I was told to avoid registering and hosting at gandi.net. What do you think about that?"

If it was meant as asked than there maybe some truth to it. But than again if you are confident in how some company handles one area than that may give some credibility of their work in other areas.

When I started using gandi they were just a domain registrar. And I am yet to use them as hosting provider.

I agree somewhat with your view, it can be true in some cases :)

I do not think about that until you give some examples or actual records.

Have you read their actual contract terms instead of their marketing materials?

If any content on your website (even if user-generated) violates their "code of ethics", Gandi can take your domain from you. There's pretty much no way to run any kind of forum, blog with comments, website with any adult content, or even a site which simply expresses opinions that are not legal in another country, without giving Gandi the contractual right to take your domain and kill your site whenever they want. And good luck explaining that your definition of "hacking" (i.e. Hacker News) is not the same as theirs.

That's bullshit.

    By accepting Our Contracts and using Our services, You agree to
    abide  to  Our  code  of  ethics which  consists,  in  particular,  of
    protecting and respecting minors, human dignity, public order and
    good moral standards, not infringing on the rights of third parties
    (private life, image, honor and reputation, trademarks, designs
    and models, copyrights, etc.) or the security of persons, property,
    the government, or the good working order of public institutions,
    and to help in the fight against abusive and/or deviant uses of the
    Internet (spamming, phishing, hacking, cracking, or attempts at
    hacking or cracking), or any other infraction as cited in the Penal
    Code.

    You also commit Yourself to ensuring that any third party to whom
    You would resell Our services, or grant a license of use, or grant
    any access or ability to modify any published Contents, will fully
    abide by the terms and conditions herein, and that You are able to
    effectively guarantee this commitment with regards to Gandi, and
    You remain fully responsible in case of violation of this  Contract
    and/or violation of laws and legislations in force, without prejudice
    of Your liability towards third parties

    ...

    You acknowledge and accept that the use of Our service: 
    • is  expressly  forbidden  for  use  in  any  way  that  engages  or
    participates  in  practices  that  are  deviant,  abusive,  illegal,  or
    prejudicial, and
    • must be done so in a way that is strictly legal and that respects
    all applicable and regulatory laws, and if applicable, the country
    in  which  You  are  located  and  perform  Your  activity,  or  the
    destination where You propose Your products and services,
    • must  notably  respect  the  rights  of  third  parties  (intellectual
    property rights, personality rights, image, honor, and reputation
    rights,  and  the  right  of  privacy  and  the  secrecy  of
    correspondence), and
    • must be appropriate to the age and sensibility of each of the
    individuals that any of the content is destined for, directly or
    indirectly,  published  or  made  available  to  via  the  technical
    solutions used.

...and that's just part of it.

http://www.gandi.net/static/contracts/en/g2/pdf/MSA-1.3-EN.p...

Ok, give an example of on actual contract terms that does not contain such part.

There is no other registrar with terms like that. None, at least among the well-known ones. A code of ethics against deviant use of the internet is not a standard contract term. Only Gandi has it.

Here are several hundred examples for you: http://www.verisigninc.com/en_US/products-and-services/regis...

w/e