Built-in phono stages

My Mac preamp has a built in MM section. It works for me, though I have not tried anything else for awhile. But I am looking to see what else would be better. Everything I have read is that the mac phono sections are pretty decent.

I have the Halcro DM10 which has the built-in phonostage for both MM and MC cartridges with 3 stages of gain for the MCs so LOMCs are no problem (I'm currently running ZYX Universe and Dynavector DV1s).
The beauty is no interconnects and additional boxes as you state (my friend has the full Aesthetix Io Signature which takes up serious shelf space).
The phono stage in the Halcro is as good as the linestage and the DM58 monoblocks themselves.
Lack of flexibility?.....nothing prevents you from adding an additional phono-stage to plug into a line input any time you wish?

The phonostage in the Ayre is very good. Same board as used in the P-5XE. The best I have heard in a preamp. The K-1XE is also the one of best SS preamps I have heard.
I also got a chance to hear the new Mcintosh C2300 preamp and was suprised at how good the MC stage was in it.

VAC Renaissance Signature Mk. II

One of the poorly understood issues with preamps is that they must control the interconnect cable. The technology to do that, to obviate the effects of the interconnect cable, was developed nearly 60 years ago, but it rarely gets used in the home (that technology BTW is known as the low-impedance balanced-line system).

Outboard phono sections face this issue, just as line sections do: in most high end audio systems, the interconnect cable behaves like a filter, filtering not only frequencies, but impact and staging information as well.

The only ways to avoid this are 1) equip the stand-alone phono section with proper cable-driving ability (none that I know of have this BTW) or 2) build the phono section inside the same box with the line stage, thus avoiding the connectivity issue altogether.

Solution 2) above means that for best operation, the preamp's power supply rails had better be quiet! so as to avoid interaction.