The real advantage to the spectra is that's an all in one system and looks ok if one doesn't have an enclosed top.
the reflectors are inferior compaired to the lumenbrights or lumenmax stand alone.
The price point is quite high new. $1500 plus $450 for the ballasts. $1950
If one were to buy 3x lumenbright mini (would be fine) that's $330 plus $450 then you'll want to add t5 (there many routes to this) but the easiest would brs retro kits or the giesemann razer. The 4 ft kits are $155 or $220 and you are looking at times 2 to compare with spectra.
All new with brs retro kits = $1050ish or $1170ish for de
With giesemann razors= $1220ish or $1350ish for de
These prices do not include bulbes. If you want to run Radiums, you'll want the SE fixture Radiums are $80 ea annually. There are other cheaper bulbs that are high quality as well, the hamilton 14 or 20k for se or phoenix 14k for de are all nice. And run about $50 to $60 ea.
Buying used is an option as well I've no idea how easy it would be to get a spectra used. I switched back to mh last year and paid a TOTAL of $350 for 3 ballasts and 3 lumenmax elite reflectors. That is not an uncommon deal on r2r. Anything around $500 is average.
I do not supplement with t5. I feel the Radium bulb does not require it (the Hamilton 14k does IMO). Instead, I use 2 ai led fixtures to supplement. With that I get the sunrise/sunset effects and moonlights. I run then through the neptune apex.
Hope that's some stuff to think on.