I've had one since early Dec 2008. I haven't had any real printing time since then, but I have run a number of film tests and used the DA enlarging meter for densitometry. The readings are extremely stable (seldom vary by even 0.01 stop over 15-30 seconds) and repeatable, and the response appears to be very linear (or perhaps one should say very smoothly logarithmic). Nicholas is great and very forthcoming with tech support.
It reads in stops to two decimal places, designed for direct use with the DA timer, and stops can easily be converted to seconds for other timers by raising 2 to the displayed stop number, e.g. a reading of 4.30 would give you 2^4.30 = 19.7 seconds. I keep a calculator right beside my timer for this.
I think the real limits with an enlarging meter arise from your own ability to visualize the final print, and where you want the tones to fall.
That being said, the DA enlarging meter is an excellent, very high quality and accurate tool, beats my old Beseler Analite 500 by miles for stability and accuracy, and I would suspect does the same to other meters like the Ilford EM10, which I haven't used. The data sheets that Nicholas supplies for several papers are also very useful for determining contrast and exposure.
I consider it well worth the price.
Lee