I have over 1800 hrs on senecas mainly fives but 4,3,2 and 1. I also have quite a few hours on the 303 Crusader.
Firstly the speeds are not far off. The Seneca being slightly quicker and the five especially is far better in the climb.
Having said that the five is far better than the earlier senecas anyway.
The Crusader is a joy to fly and feels very like a baby Golden Eagle. Superb views from the cockpit and a larger cockpit.
Handling is very crisp and the aircraft is superb at short field. Infact I was using this aircraft into 500 metre strips.
The undecarriage is built like a tank and has an amazing 175 kt lowering speed which means you can drop the undercarriage in the cruise push the nose over and see 3000 fpm descent.
The aircraft has an airstair and a far better carrying capacity than the seneca.
The aircraft was built over a very short period of time 82-84 and was brand new design rather than a 50 year old design like the seneca.
It even has engine fire extinguishers!
We had a lot of problems with an engine surge on ours which happened above 5-6000 feet an got worse the higher you went.
The engine really is the weak link. I feel the airframe needed a more powerful engine than the 250 horses available.
There was also a pitching tendancy in icing which was caused by icing on the cruciform tail junction. I believe there was a fix for this.
Altogether a very smart looking aircraft with delightful handling seneca speeds and fuel burns but better carrying ability.
All the best
Pace