I'll give a hearty endorsement to the 1587 "Insulation Multimeter". I have made good use of one in a harsh industrial setting that requires a full function DMM as well as a megger.
It is a true full-function DMM covering ac and DC voltage, ac and DC mA, resistance, temp., capacitance, and insulation tests from 50-1000 V.
It does not have the 0-10 amp scale common on most DMM's, but I have never missed the feature. I do have other meters and a clamp on at my disposal should I need to measure in this range.
It has one flaw/gawdaweful annoyance - if the meter is left sitting for a week or so w/o using the megger feature it will give a false battery failure warning when first powered up. I'm on my second one that does the same thing. You have to leave it powered up for a couple of minutes and it clears. It helps to grit your teeth, stomp, and cry a bit, too.
I like the 50 and 100 volt megger features, I have used this feature often to address random fuse failures on damp 120 volt control circuitry. I also like how the meter displays the actual test voltage, with a bit of experience you can ID things like VFD's hung off a bus or get a better feel when you get a low resistance reading when checking out a motor and wiring.
An example of this are two recent cases where there were catastrophic failures in MCC buckets that had resulted in tripped department switches with fault currents logged in the 8-9k amp range. Prior to actually finding the faults I meggered the MCC bus at 3-5M ohms. Not good, but not what you'd associate with thousands of amps of fault current - until you read the test voltage at 80-90 volts when testing at 500. An open circuit or good bus will normally display a test voltage of 525v. Further inspection in both cases revealed extensive arc flash damage and the resultant blast residue inside of buckets, one on top of the breaker, the other within.
I would like to have had a hand cranked version to see if it would have given me a more definitive measurement result.
I have compared the 1587 to a couple of the high powered hand cranked jobs and have gotten similar results on other good and marginal test subjects.
The 1507 is its' smaller brother with what I consider some limitations you should consider:
1.) The resistance function is limited to values less than 22k ohms. Any reading above that is simply displayed as >22k ohms. I'm an electronics guy lost in this electricians world, but this one bugs me, and it makes the meter useless for some of the explosion suppression equipment I work on.
2.) The meter is sensitive to induced voltages on unenergized wires in an industrial setting. I have seen them give a "voltage present" error more than once and I was able to make the measurement with my 1587. I did measure an induced voltage of about 1.5 vac, which is pretty insignificant considering the impedance of the meter.
3.) The 1507 push button is an annoyance. When in the DMM mode the 1587 operates like any conventional DMM we are all used to.
A word on the push button for both meters when meggering - The push button applies the test voltage but also bleeds of the charge when released. Proper technique is to contact the circuit to be measured, push the button to make the measurement, release the button, and only them remove the probe from the circuit under test. Otherwise a large motor on a long run of wire can remain charged and make for a real eye opener the next time you touch it.
FWIW, the last round of guys (4) hired here were issued the 1507. They were just reissued 1587's last week.
For me, the 1587 is awesome.