Futsukei-rashii & Futsukei-sou dou chigaimasu ka

[mrcharlie]

例：
A:　田中さんは結婚するらしいいです。
B:　田中さんは結婚するそうです。

A と　B　と　どうちがいますか。

[QuackingShoe]

http://www.guidetojapanese.org/similar.html#part5

[mrcharlie]

ありがとうございます

[mieth]

first the usage of rashii is used to expressed that something seems to be a certain way. It could be based on sense such as sight touch sound etc., also from a hearsay source but when you use this with the personal you are talking with you are not assuming a large amount of liability if the information ends up to be incorrect. It is kind of like well this what I heard it may or may not be correct but it seems to be this way.

The usage of sou da that you used is a direct relay of information that was received from another source. It is simply relaying what was told by the speaker. This also does not leave much liability with the speaker in regards to the validity because he is simply restating what he was told.

there is another sou da which is attached the masu stem of the verb. Which is a guess of what you think will happen based on some current physical stimulus.
ame ga furisou desu. In this situation the sky is probably overcast and the speaker is physically outside or looking outside through a window.

There is another form which is you desu. this is a grammar that is used when you are coming to a conclusion based on strong consideration of the situation at hand. The person is likely evaluating physical evidence or looking up information in regards to the situation for which he is making the conclusion. Essentially the level of thought is much higher than with the other usages.

anyway hope this helps