You know I had thought about the Jadgpanther due to its low silhouette. So, if i'd base it off that I would even consider the stug IV, fast firing, highly mobile. I chose the Jadgtiger due to it's armor being so thick nothing the allies had could penetrate and a tank destroyer's job was to slug it out with tanks.
I do like the M18 but it had to be supported by infantry. It couldn't go patroling off on it's own. Alot of its success was due to allies owning the air. A open concept turret doesn't do well in AH. Also, check out combat tactics on how the M18 was used. A sorta stand outside the box type of vehicle that provided overwatch for light to medium armor.
I have to agree that the tiger did have some issues on mechanical failures. While living in germany I lived in a town called Wiesloch. Every year they have a festival called Winzerfest. It's a week long celebration of bringing in the new years wine. I sat down at a table next to these nice elderly german couple. After a few glasses of wine and some small talk I found out the elderly man had served in WW2. After a few more glasses of wine and some reassurance that I had no political views and was actually interested in his service he opened up a little. Come to find out he was a 17 year old panzer driver. He had driven alittle bit of everything during his tour. He said that the tiger I could take an incredible amount of damage. Suspension and road wheel damage, Short of loosing a tread a tiger could basicly lumber along. The main disabling damage caused to tiger he thought was when the gun plate got damaged and the cannon couldn't be elevated or depressed. He stated that if Germany had been able to recover their vehicles like the allies did they wouldn't have hardly lost very many. Most tigers lost in combat were due to the crews leaving them with no fuel. He also told me that during a bombing that if a tiger crew stayed buttoned that they would be fine. The biggest problem would be the pot holes left by the bombs some got stuck but not destroyed. Well, I obtained this through 3 nights of wien and food. While in Germany I also met Adolph Galland's granddaughter but that is another story.