I have a Delphi MkII/III with a Sumiko FT-4 Arm. The MMT was their entry level arm (about $300) and they sold tons of them, The FT-4 was $550. At the time Sumiko also sold the SME 309 for $950 and the SME IV for $1500. (To give you a frame of reference on the arm.) The MMT was the respected entry level arm of the day (When Rega wasn't available). The FT-4 is from the same family as the MMT with upgraded bearings, wire, & etc. Though it does a nice job, I intend to replace it one of these days, but feel that I would need to spend close to a thousand to make a difference.
If I were you, I would put the Grace on your table. I think it is the better of the two arms and put your $400 toward better cartridge. I run a Grado Sonata ($500 retail) and am very happy with it. If you want to start out on a tighter budget; the Ortofon OM-30 was recently favorable reviewed by TAS. I used to run Ortofon OM series MM's on lesser turntables and they sounded very good. Good Luck.
If I were you, I would put the Grace on your table. I think it is the better of the two arms and put your $400 toward better cartridge. I run a Grado Sonata ($500 retail) and am very happy with it. If you want to start out on a tighter budget; the Ortofon OM-30 was recently favorable reviewed by TAS. I used to run Ortofon OM series MM's on lesser turntables and they sounded very good. Good Luck.