First of all, Hunny I saw that question and your advice to that brother was perfectly appropriate. He was looking for women online, and wanted to know how to meet JW women online, which is not in harmony with the counsel we have received, and would likely not work out well for either party. It was good to tell him to 'back off' a bit! :)
For Vot, I have been married and am currently in the process of divorcing. My husband fell into the category of what Granny described above. There were times when our marriage was absolute bliss but other times when it was an absolute nightmare. Only because of worldly habits he adopted/fell back into, though.
I really think that for two people who love Jehovah, they can make their marriage work if they just apply the counsel we've received to put Jehovah, and then each other, first. Marriage is a wonderful gift.
With that being said, I am finding out that singleness also has its advantages - I have so much more time now! I can eat an apple for dinner if I want, without having to worry about how hungry anyone else is. I can hang out with friends without worrying about my husband feeling left out. I don't have to clean gross toilets and showers!!! ;) The biggest advantage of all is that I can really focus on spiritual things.
There are many things I miss about marriage, but there are real pros and cons to both sides. Marriage can be an amazing, wonderful thing when you both love Jehovah and are committed to making it work. But it can be worse than you could possibly imagine if you find yourself with the wrong person.
Anyway, to answer your question, I think sometimes the person telling you to wait for a "perfect mate" just thinks so highly of you that they don't want you to marry someone who isn't as spiritually minded or mature. Or, in other cases (I don't think this applies to you), they may feel that the person is focusing way too much on finding someone and not enough time working on their own spirituality/maturity.