First, the last time I read CR on paint was probably
10 years ago and even then they only reviewed
acrylic paint. Their assessments should be taken with
a grain of salt. In order to assign ratings they cook
up categories for testing somewhat willy nilly, rating
products for largely irrelevant things like "ease of
cleanup" or "spreadability". The main factors are
coverage, settling and durability. And CR can't really
test for durability.

It's a tricky issue. Oil is better for exterior,
especially for horizontal surfaces like window
sills. Acrylic paint simply doesn't resist moisture.
Many painters will tell you acrylic is the way to
go because the pressure is on to convert to
water-base, and because water base is easier
to work with. Probably many younger painters
don't even know how to work with oil paint
because they've never needed to.

Though oil is better, oil paints have been generally
downgraded to meet EPA requirements and to save
money. At the same time, acrylic paints have improved.
But the technology simply hasn't kept up with the EPA
restrictions. * There are no current paints that compare
to the quality of what was available 10+ years ago. *

I still have some old Benjamin Moore oil house paint
that I use for things that need to really last. For ground
level trim I'm now using Cabot's oil stain. But the Cabot's
is not what it used to be, and other companies are
no longer making solid oil stain. (I know you're talking
about gloss, but gloss this year is flat 2 years later
on exterior.

B Moore and Sherwin Williams both have exterior oil
that I've used. BM version is called DTM. (Direct to
metal.) They can only sell it in quarts and apparently
have to say it's for metal, but I use it on wood. I
haven't seen the longterm results for either of the
newer oil paints, so I'm not sure what to think. And
I'm not sure if either comes in high gloss. I've only
used the satin.

If you want a tough, slick, high gloss finish the best
might be B Moore urethane reinforced oil. It's typically
used on exterior floors, but should be OK for trim. If
you can find oil base high gloss Impervo that's very
good, but it's being phased out.

If you go with acrylic it won't be as tough and you
can't get the same handsome sheen because it
doesn't settle down as flat as oil. The film is porous.
But if you prime or spot-prime first with linseed oil
primer you should end up with a reasonably durable
finish. (Linseed oil primer is important because it's
the only type that will really soak in to the wood,
which is really the main point of a primer.

Sorry to go on so long with such uncertain conclusions.
It's just the state of the market. I've been doing painting
commercially in my work since 1980. (I do some painting
work and a lot of renovation/building work on which I also
do the painting.) I used to have clear answers to questions
like yours, but there just isn't a best answer anymore.

Last week I was trying to hunt down solid oil deck stain
for my own deck. It's had Cabot's stain for many years.
I'm not sure if I'll be able to get the Cabots. Acrylic deck
stain is a bad joke, wearing away in less than one season.
Urethane reinforced deck paint is good, but when it peels
the scraping is hard work. Then there are new "high tech"
products which may be good.... but who wants to be a
guinea pig? That same dilemma also applies with exterior
house paint and interior trim paint. The best options just
aren't sold anymore.

If you want a really nice look I'd go with the urethane
reinforced oil. If you're happy with a decent finish the
acrylic will be fine and should hold up OK on vertical
trim that doesn't get too much weather exposure. Just
don't buy junk like Glidden or the stuff you can get at
Home Depot. I've used B Moore for years. Then I
switched to Pratt and Lambert, as BM has been going
downhill. P&L is consistently very good, but Sherwin
Williams bought them and now I can't get P&L. I'm
currently using mostly Sherwin Williams, with somewhat
mixed feelings. Any of those 3 brands should be good
enough.

With the black color: That's a matter of taste, but
personally I think there's nothing more elegant than
a very glossy and very smooth black finish. If it
were me I'd be happy to stick with that.

Also, a note on cleanup: If you get a decent polyester/
nylon brush and leave it soaking in thinner, then also
buy a spinner to spin it dry before use, you can go for
weeks or even months with the same brush. You don't
need to buy lots of junky brushes and throw them out.
I just keep one acrylic and one oil brush, both soaking
in paint cans inside 5 gallon compound buckets. By
leaving them soaking and using a spinner I never need
to actually clean a brush, yet I always have a high
quality brush ready to use. Just don't use bristle that
way. It will quickly stiffen in the thinner bath.