Krell KAV-400xi vs Musical Fidelity A5

hello, i currently have a mhdt havana for my dac and i'm looking for a nice SS integrated under 2k

are these two good choices? any better recommendations?

what are the differences between the MF and Krell?

Personally, I would go for a slightly used Krell S300i. You can get one for ~ $1750. Its much better than both amps you mentioned.
I have an A5 and think it is a great piece, and bonus a decent built in Phono pre. Neither Krell will offer you that. BUT it is going to depend on what speakers you are using...
I listened both of them with various speakers and I must admit I didn't like them ... I believe there are much better choices on the market for the same amount of money. Krell new baby S300 seems much better choice ... I would also take a look into hybrids like Pathos or Unico - they have models that cost even less and provide much more vivid presentation.
To my ears, while I haven't heard the 400xi, the A5 offers much greater resolution and is far quieter than the Krell s300i (which had an audible hiss at all but the lowest volumes). The Krell's only advantage was in the bass, and that was slight.