Since I have been looking at 800 up through 2000 series, the DHO804 is bare minimum to buy, you can then "upgrade" it to the 814. Also limited to 100MHz spec, -3db should be somewhere near 180MHz. Albeit single shared ADC.
As for mixed signal, sorry just have to comment on it, the SDS1104X-E is on sale now and comes with digi bundle SDS1000X-E-FG and SDS1000X-E-16LA for $475. This SDS can also be "upgraded" to 200MHz. Dual ADC.
Each has their own learning curve and are different, but nothing drastic.