I believe that Jesus came to set us free from the Levitical laws and ordinances-all the things that were so very hard for them to keep in those days. But if Jesus set us free from keeping the Sabbath, then it must mean that it is also Ok to lie, murder, steal, and break the other 9 commandments etc. And we know that is not true! There is nowhere in the Bible that says Jesus told us to stop observing the Sabbath, unless I've just missed it. He says to keep His commandments, and He doesn't say to just keep 9 and not all 10.
I don't go to a 7th day church, because I have heard that they base their salvation on the works of keeping the Sabbath. I think that the whole term "Sabbath" means to REST on that day-not necessarily go to church, because the Bible shows us that the disciples also worshipped on "the Lord's Day" which is Sunday, the 1st day of the week.
I keep the Sabbath, but I don't get all legalistic about it- I don't work on Saturdays-I rest and spend that time with God as much as possible. I go to church on Sundays though, and any other time they are having services. I certainly don't base my salvation on whether I go to church on Saturday or Sunday though-I base it on the fact that Jesus died for my sins!