For me, the biggest advantage was cost and flexibility of both choosing components (SSDs and drives) and quantities of each that make sense to me to fit my use case. Traditional SAN you buy more storage than you need to plan for future storage. VSAN you can buy just what you need and easily upgrade adding 1 disk at a time or expanding additional nodes. As an example my remote offices are using 5 of 12 drive bays on nodes and expanding capacity only as necessary. I have the flexibility of increasing storage 1 disk at a time. Traditional SAN, i'd have to buy a smaller node limiting where upgrades involve buying new units or buy the full filled out node with wasted storage.
Also I really like the rebuild logic of VSAN, normally when a disk in an array fails, there's a RAID rebuild involving every drive which causes massive I/O on rebuild. VSAN only the contents of that single disk are rebuilt, if a 4TB disk fails, only 4TB of data is involved in the I/O resync process instead of an entire array of disks rebuilding for a day.
In terms of cost, my DR site is:
5 Dell R730xd nodes. Each with 1xIntel E5-2650, 384GB RAM, 2xIntel P3700 1.6TB NVMe, 14x4TB WD Re4, 10GB redundant networking using Arista switches and Cisco firewalls. Whole setup cost ~$155k (network equipment, VMWare Ent, VSAN Std licensing included) providing 50 cores CPU, 1.9TB RAM, 125TB (250TB raw) usable RAID1 storage and it's pretty damn fast. If you exclude compute + network + VSAN licensing from my cost to price out what I would have normally shopped for storage, that gives around $65k to buy 250TB raw from a storage vendor, good luck with that....
I have run into similar issues too as Zach has, make sure your DR software or any ESXi integrated software fully supports VSAN. Also I have had nearly every bug applicable on the VMware support KBs involving VSAN affect me and some are quite serious. Make sure your environment is fully patched and you stay up to date with the KB articles applying any necessary workarounds/hotfixes and contact support at 1st sign of problems, VSAN is still somewhat new and some (mostly minor) bugs.