Better is subjective. If you can afford it, and you want top performance, SSD will do that. The hybrid gives you four times the storage space, and is a lot cheaper.
Pros/cons: the hybrid drive (older part) can allow data recovery if the drive crashes. This could be comforting or not. The SSD will eventually fail like a lightbulb: poof-no data. --unless you have access to a data lab with a STM & plenty of research time.
Yes, the 4 gb will make a big difference. This isn't just cache memory, but a full SSD system. Check the performance times on reputable sites. If you are doing statistical modeling, editing movies, or otherwise manipulating huge files, then the 4 gb may not help so much. (probably, neither would the limit of a 128gb SSD)..
Apple wouldn't offer the hardware-especially at their prices, if they thought users would be disappointed. 300-dollar computers- they can be disappointing.
Bottom line, nothing is going to beat an SSD on performance, but they are expensive and smaller than other drives. A compromise in the hybrid drive (and lots of ram) is the next-best, more economic solution.