Can't speak about the other brand you mentioned, but main difference on SE PRO and TLD/ADIDAS ULTRA on the pants are:
• different waist enclosure on the Ultra....2 button slim snaps on Ultra vs the SE PRO with a classic moto ratchet, and the ULTRA has side micro adjusters. The ULTRA is more similar to a premium mountain bike short/pant waist adjustment, your gonna have a little less bulk in the front of the waist on ULTRA.
• More laser cut precision ventilation on ULTRA vs SE PRO, mostly in the lower legs, when your pants are tucked into the boots, more cooling with the ULTRA
• construction is a bit more advanced on the ULTRA, taped seams, a bit more articulation on ULTRA
• that baby soft, yet durable lambskin leather on the knees with ULTRA
As for Jerseys, the differences between the two are not as drastic as the pant, a bit more laser cut ventilation on ULTRA than SE PRO, and the high end silicone logo hits on ULTRA give it a more premium look and feel.
I run the bicycle division for Troy, so, while I don't know our MX line inside and out, I know we are going to launch a Bicycle version of ULTRA in March too.
Cheers