Bridges can be hit or miss. I've grabbed bridge IPs that didn't work, then I grabbed some more and they worked. If they don't work for you the first time, you can try new ones. Will regular bridges mask your Tor use from your ISP? Yes, if they are only looking at IPs. If they are using deep packet inspection to examine the stream, then probably no. But if you're in a western country, chances are very high they're not looking at your Tor use in the first place.