Both. You can't know for sure if you'd like them, so your best option is to watch both. However, you should start with TNG Season 3, since the first two seasons suck and TNG was made earlier than ENT.
For ENT, I suggest that you start with the first few episodes, and if you don't like them enough to watch the series in order, ask for a list of good and significant episodes from the first two seasons on the ENT forum. After those episodes, start watching the series in order from the S2 finale on. (Season 3 is extremely serialized and Season 4 embraces the prequel concept of the series. Both are much
better than the first two.)