might be a bit late, but, Roland Junos are cheap and cheerful synths designed for the beginner, or those with a modest budget - they sound good, they're easy to program, and you will learn all the basics.
In contrast, the D-50 was a flagship synth, designed for the power user - in 1987 the pitch was a D-50 could replace your DX-7, your analog poly, and take the load of your 8/12 bit sampler.
If you get a D-50, you'll find that you can copy all the sounds of a Juno (albeit in a digital kind of way), but if you get a Juno, you can't copy all the sounds of a D-50.
The Junos are much more immediate, and for all their limitations, are good little synths, and you'll be able to tweak away from the very start.
Of course you could get a PG-1000 ( or similar) for the D-50 for the immediacy of knobs and sliders, but the synth engine is more complex, and if you don't have any prior experience with subtractive synthesis, the D-50 could be daunting. Without a programmer box, the D-50 uses what used to be called "Digital Parameter Access", that is, one parameter at a time editing. Coming from that era, I'm used to it, but some find it a bit tedious and counter-productive.
I think either is a good choice, and which ever one you chose (or choose) you'll have for a long time.