Serious newbie oldie seeking film advice

I've been taking pictures seriously for several decades but I haven't used
my Bronica in over 10 years and I want to take it on a forthcoming trip to
Hawaii. I'll be photographing mostly flowers and, hopefully, some birds and
maybe a sunset or two. Since it's been a long time since I've bought any
120 roll film, I was somewhat surprised to find that all of the old film
types I knew are no longer made and I have to choose between -- in color
negative -- Ultra 100, Portra 160 NC and Portra 160 VC. After reading the
stuff on the Kodak web site, it looks like Ultra 100 would get me the "best"
pictures but I'd like to hear from some photographers who have used these
films and have experiences to share. FWIW, I expect to be shooting with a
tripod so film speed isn't a primary consideration and I'll probably be
making 11x14 or 16x20 enlargements, either directly or after having the
negatives professionally scanned.

As a subsidiary question, would I be better off using one of the Ektachrome
slide films?

TIA
Norm