I can only offer my opinion. I have the NIDNTT but not the abridged version. I have both the NIDOTTE and TWOT.
First, I suggest you read the descriptions at Accordance's website. These can be quite useful and especially the screen shots.
Second In this case of the comparison of the NIDNTT with the abridged version. Here are the distinctions that I see. 1. the classical usage and Old Testament usage have been combined in the abridged version. 2. It appears that most of the text is there with some very minor changes in wording. 3. The most perceptible difference rather puzzles me. The unabridged NIDNTT structure is to use the English term and then the various Greek terms under it. The cheaper abridged version seems to be structured around the Greek terms themselves. I guess I would have expected the reverse. It should not matter, however, if you amplify from a tagged text to the lexicon it would take you to the appropriate word in either case. If I were purchasing it for myself again I would go for the cheaper abridged version.
Third, the comparison between the NIDOTTE and TWOT is much more subjective to me. I have had the TWOT in print for years and thus seem drawn more to it. On the other hand the NIDOTTE has some very valuable essays its beginning. It really is a much more comprehensive module. Of course you did not ask to compare those with the HALOT and BDB Complete but I have done so anyway. I have attached two screen shots for you to see a comparison.
My recommendation is if you are going to buy one Greek Lexicon and one Hebrew Lexicon to grow into and use for years to come, then buy the BDAG/HALOT combo.