A Record number 3 is the most recent plane I've added to my collection, and I really like it. I set it really fine and use it for finessing small areas. I also have a GTL brass plane which is the same size.
When I'm doing a lot of planing I'll have three or four planes set up. A scrub plane to remove a lot of material, a jack plane or number 6 to get the surface flat, a number 4 to get a really smooth surface, and then have the number 3 for small patches that just need a little extra work with a very fine cut
So I like the number 3, but I wouldn't buy it as my first plane - I'd get a number 5 as my first plane. Also I'd buy a 4 before I bought a 3.
But there is nothing wrong with a number 3. Perfectly good plane. It small size lends itself to light finessing of a surface.
You can also pick them up very cheaply. I think the Record was a steal at £30, and it's not hard to get a good number 3 around that price.