With ESXi, it's really hard to beat something like an LSI 9270CV-8i (available with flash and supercap on eBay for $100-$150 often enough) as a local storage controller. It does take some research, and you can definitely run into issues if you're not careful, but a pair of SSD's in RAID1 on a 9270 is about the fastest non-NVMe storage available and it is wicked fast. 1GB cache. You can move on up to the 12Gbps stuff and get a bit of a bump but that's like $700 for a fully outfitted controller.
The great thing is that it's a Real RAID Controller, used in enterprise environments, and it can easily be set up so that stuff like "pull failed drive, insert new drive" automatically does the rebuild, or that you can have a warm spare drive, and it will automatically rebuild on failure, and the idiot lights light, and there's no "oops I forgot to configure the disk in the host platform" so often associated with software RAID platforms. My favorite configuration is 3 x WD Red 1TB 2.5", 2 in RAID1/1 hotspare, 5 x ~500GB SSD (Intel 535, Samy 850, etc) in two separate RAID1 and a hotspare. You can actually make an I/O subsystem with tiers, including HDD, a high endurance SSD tier, and a light-use SSD tier, protected with hotspares, very inexpensively. The downside is that as a Real RAID Controller, you have to make sure you do things like disable WDIDLE on those Reds, and expect to have to do some learning about how to make the thing work.