Although the recipe said it'd be 4 days until the pickles were ready, we couldn't resist and tried them on day 2.
Verdict: Both husband and I prefer the batch with no fennel seeds. Oddly, the batch without the fennel seeds seems a bit hotter, although I put in the same amount of pepper flakes into both jars. I guess the fennel masks the heat a bit.
That said, both jars are good. Best of all, pickling the turnip makes it edible! It's good to find a way to eat the purple top turnips that have accumulated in the fridge.
Will update on day 4, when the pickles are officially ready.
[Edit: We missed day 4 completely. Pickles were still crunchy at one week after pickling and the flavors were better melded than they were on day 2.]