https://www.eevblog.com/forum/reviews/new-instek-scope-gds-1072a-u/msg62080/#msg62080Either is oK. Based on Amazon.com pricing, for extra $150 you pay for less MHz on the Instek, you get a lifetime warranty by a reputable company. Insure you read the warranty conditions of what 'lifetime' really means; in the case of Fluke 87V lifetime was defined as 10 years after the model line is discontinued, IIRC. Rigol has had its share of bugs with the new firmware, but most are resolved and existing ones are mostly assembly issues, so for both scopes its essential to have an authorized distributor you can return the defective one for an easy replacement.
I've never heard of anyone complain of bugs or defects in an Instek scopes though, in my years at eevblog, but there are less discussions about their products than Rigol, Hantek, Owon Agilent, and Tek.
Dave has done the world a service by the tear downs, one thing you notice in Rigol is that they do not use non-name components [mostly, it seems the maker of their rotary encoders and plastic knobs are not as good as their choice of electronic components], even in the 1000s series, giving it a high probability of living far beyond its warranty period, but like all infant mortality periods or when the item is fresh out of factory, it has to live well for the burn in time to insure you don't have one with an assembly defect. This is were the 3 years is more than generous.