If you talk with a salesman for amateur antennas that is connected to the company that makes the product you are inquiring about, he will tell you its the best thing since Nikola Tesla, because it puts $$ in his pocket. I've scoured the Dayton Hamventon for 25yrs talking with all the antenna mfrs and they all have wild false claims about their products and how theirs will outperform the guy across the isle with a similar looking unit.
The SGC tuner guy will tell you their tuner with a whip is better than a resonant antenna which is a lie. The Yaesu guy will tell you his ATAS dummy load will work about as good as that $1,000 screwdriver, which it can't. The GAP guy will swear their antenna will outperform a Cushcraft or Hy-Gain or Hustler vertical when in fact it doesn't. And by a long shot. In reality the guy you are talking with probably has no clue and is told what to say and most of the claims are BS. This is especially true with wire antennas. Commercial antenna specs are a little more trustworthy on gain and pattern figures but not amateur. Ok maybe you can believe the specs from M2 antennas or MyAntennas and a few others but its rare.
So while most people are getting up and going to work every day, I'm probably out testing more antennas in the field to see how they work and how far fetched the specs are. That's what I do. And since we are talking specifically about the Ultimax, which is a 9:1 balun type, they are proven time and time over to be inferior to a resonant end fed half wave of similar size. When you shrink them down smaller than a similar band EFHW like 24ft long, they are dreadful.
Even Danny at MyAntennas makes a 9:1 type end fed only because he can't convince some people that resonant EFHWs are superior. His 9:1 is built better than the Ultimax and handles about the same power for a similar price but if you call him and ask about it he will plead with you not to buy it and to get an EFHW instead, because he wants you to be happy. That's how bad the Ultimax and the Maple Leaf and the EARCHI, and all the other 9:1 types are. But you won't know that reading their advertising.
If you find a cooperative salesman, all the better. If you don't trust catalogs, I'm sure there are spec (data) sheets available someplace (if the dealer doesn't have them, I've had good luck on either the Internet or from the manufacturer directly)--unless you don't trust those, either?