I have the 105 2.5 Nikkor and the 135 2.8 Nikkor. The 105 is brilliant as a single portrait lens, landscape lens and general 105mm lens; I've had mine for about 23-25 years and used it endlessly and never been let down.
Since the last 23 years I have generally travelled light when flying overseas with a 28mm - 50mm and the 105mm.
A few years ago I picked up a mint 135 AIS 2.8 Nikkor. It is pretty much as good as the 105 lens but has a slightly better pulling power and of course a better close focus out of focus background compared to the 105mm.
I am currently sitting in a Spanish house in Priego (Cordoba) and I am travelling for a few months in Europe with the 28mm, 50mm and for the first time, the 135mm.
I decided to take the 135mm as it has more pulling power for buildings and/or landscape features one often meets in Europe. Tesdting last year told me the 135mm was as good as the 105mm as far as I could figure out. The 105mm Nikkor has been the best lens I have owned in the Nikkor range. The 135 AIS 2.8 Nikkor is, from my experience, equal in all things the 105mm 2.5 AIS Nikkor is. Both lenses have built in lens hoods, take 52mm filters and are both reasonably compact.
The 135 fits inside my jacket pocket, as does the ever so slightly smaller 105.
If you have the opportunity to pick up a good specimen of the 2.8 135 AIS Nikkor at a price you can afford and are hankering for a reasonably compact and reasonably fast 135mm lens, then do so, I don't believe you will be disspointed.
Mick.