I have one tank with Kessils - amazing light, especially the new "tuna" version (tuna=tunable I don't think they quite got their market research straight on that one
) as both spectrum & intensity can be controlled manually or with controller, this system came out well priced for led quality & "accessories" (ie the bits that let you actually mount the light & controller etc - cables sold separately! some of the packaging on LED is just absurd, so be detailed when comparison pricing) in my area (a marine shop that does some freshwater lighting & misc on the side).
My other tank has an older T5HO luminaire with 4 lamps that run in pairs (lamps 1&4 or 2&3) - take note of which lamps are paired & if lamps can run independently - manufacturer does not support dimming ... this seems to have changed with newer T5 luminaires but confirm before you buy (again this usually means controller budget, but also ask about lamp effects).
I use Giesemann T5's for spectra/CRI preference (really not a fan of the pink "plant lamps")
When looking at T5's pay attention to lamp & light spread - I have this on an 18in width tank & there were very few options with lamps installed over a 16" spread (I rarely use lamps 2&3).
I really like the light effect of both tanks but LED is far more versatile (T5 units & lamps are very much on their way out in my area) & can be far more minimalist in appearance.
When looking at LED luminaires, pay attention to the led array re even light distribution over length & width of your tank (eg I didn't like Maxspect's 90 cm lamp option) ... unfortunately getting PAR diagrams out of manufacturers is complex
Advanced Aquarist has some terrific articles on LED & PAR & PAR sensors & ...
Sanjay Joshi does some very detailed reviews - not the article I'm thinking of, but still gives a good idea of how light strikes the tank
OK a better
search result
While you're researching light options, you can get your hardscape ordered in & play with scaping (or just
go Dutch like Pedro Rosa ), sort out CO2 system.
I've finally used Tropica Soil in a recent scape - rave review!
You mentioned "cool running" of LED in your initial post - this is very noticeable during summer months.