As a platform it is a priced platform from IBM that runs on Intel and emulates the IBM Z instruction set as well as abstracts I/O.  In general it is used as a low-cost alternative to owning an actual Z platform and is primarily targeted at test / development environments.  As part of the Terms and Conditions of ZD&T binaries produced on that emulated environment cannot be distributed for execution on real-Z hardware deployments.  Its not that the binaries are not the same, its simply a set of terms and conditions.  Please review the IBM Terms and Conditions to verify the current ones as I’m sure they’ll be changing over time.

Here is a link to V12 (I’m not sure what is the current version)  https://www.ibm.com/support/knowledgecenter/SSTQBD_12.0.1/com.ibm.zdt.overview.gs.doc/topics/c_product_overview.html

And a disclaimer for that version

Here is a link to the Development Platform https://www.ibm.com/developerworks/community/forums/html/topic?id=b824cabc-a0fa-4ea0-b45f-54f05d099b28

Zowe does use ZD&T as part of its verification pipeline as provided by donors outside the OMP.  Currently the OMP does not manage or provide access to ZD&T licenses.  

With that as a preamble Java seems to perform poorly on ZD&T.  I don’t know the reason for that but I’ve heard a number of speculations but never any real data.   That said, it has little to do with z/OSMF apart from it using Java as its primary operating environment. 

Other interfaces that Zowe interfaces with like the Explorer runtime as well as API Mediation layer also use Java.  The primary difference between their use and z/OSMF is that z/OSMF is much more tightly tied into the z/OS operating system and is a strategic delivery for services on z/OS.  API ML and z/OS Explorer both use z/OSMF services.  There are plans to build new functionality to limit or replace the dependence on z/OSMF and provide new means of delivering the capabilities.  

Bear in mind that z/OSMF is a collection of services and not a “thing.”

Here is a list of z/OSMF services:

•z/OS data set and file REST services - Supports working with z/OS data sets, Unix files and Unix directories such as create data set, read/write content of data sets, query data sets, query Unix files, etc.
•z/OS jobs REST services - Supports working with z/OS jobs such as list jobs according to specified criteria, submit job, retrieve job spool files, purge job, etc.
•z/OS console services - Supports working with z/OS console such as issue console command, retrieve command response, monitor console messages for specified keywords, etc.
•TSO/E address space services - Supports working with z/OS TSO address space such as start TSO/E address space, start a TSO application, issue TSO command, etc.
•Notification services - Supports working with notifications such as send a mail/mobile notification, retrieve all notification received, etc.
•Cloud Provisioning services - Supports provisioning MWs like DB2, CICS, IMS, MQ, WebSphere via REST APIs.
•Workflow services - Supports working with z/OSMF workflow via REST APIs such as creating a workflow, starting a workflow, cancel a workflow, etc.
•Software Management services - Supports working with z/OS Software via REST APIs such as add a software instance, export a software instance, retrieve properties of software, etc.
•Application Linking Manager services - Allows 3rd party application to integrate with z/OSMF applications via REST APIs such as registering event which could be handled by z/OSMF application or register itself as a handler to handle z/OSMF events, etc.
•Topology services - Supports retrieving topology information managed by z/OSMF Systems task via REST APIs.
•Application server routing services - Supports route your UI requests to a separate application server when you develop an external z/OSMF application.

As Zowe chooses to move away from z/OSMF (if that is the strategic strategy by the project) all of these functions (if needed by Zowe applications) will have to be re-written in new ways and maintained by the community.

My experience is that z/OSMF when tuned does take about 16 minutes to initialize on my ZD&T system but performs well once initialized.

I’m not advocating for one position or another (although my personal opinion is that Zowe should be engaging more actively with IBM z/OSMF team rather than rewrite function that is already delivered as part of the platform).  

Rather than using the term z/OSMF I think the more productive conversation is to discuss the services needed, the challenges and issues encountered than to simply generalize the conversation and take on a boatload of additional work that doesn’t make Zowe stronger, it puts it in a weaker position because they are competing against IBM development rather than complimenting and extending.