Hello,
There is no real equivalent to the Fluke 55XX series. Yes Transmille is not a bad device but it can't be a Fluke.
It has some pros but also cons.
For example, note that every range may not give the same measurement uncertainty.
I've used both devices, Fluke is more reliable.
A brand new Fluke can be very expensive, but you can opt for a used Fluke.
Remember, the Fluke 5500A,5520A is no longer manufactured and technical support has been terminated.
If you are not going to use scope or PQ options, the E series is cheaper. But it cannot output both volts and current at the same time.