Rotel 1520 or separate phono stage?

I recently purchased a Rega RP3 with a sumiko blue point 2 cartridge. I have this connected to a Rotel 1520 integrated amp with PSB T55 speakers. I am now trying to figure out whether I should get a phono preamp and how much would I have to spend in order to get one that will outperform the phono stage that is built into the Rotel. I've researched the sub-$500 preamps but don't know enough about the specifications listed to know whether this would be an improvement over my Rotel. Any help/suggestions are greatly appreciated.
When Ihad my Rotel RC-1082 preamp I had to upgrade to a Graham Slee Era Gold MkIV to hear a difference - new it is $1200, I paid $700 as a demo. Rotel phono stages are decent for being included in the package.
Thanks for your help. Was looking at some in the $300 range but will probably save a bit and spend a little more down the road so I can really hear a difference. Thanks.
I think the phono stage in your Rotel is pretty good for what it is. However, IMO you can get better performance thru the use of an outboard stage in your price range. The primary reason is shielding and/or the ability to place the phono stage out of the way of your amp. IMO, PP2 from NAD phono stage or musical fidelity X-lp will outperform your built in. Both run about $200 and can be found used. I found a musical sussoundings phno stage on a-gon for $300. It sounded far superior to my NAD then in use. If it doesnt sound better to you, sell it.
Thanks for the response. I do have a pretty high end audio store near me where I bought the RP3. Hopefully they have something where I can try different preamps out to see what works best. I appreciate your help.
I like the project phono vastly outperformed the phono stage in my NAD preamp....