TL;DR: Yes, go ahead, they’re good, we like them.
I won’t say they’re perfect, but we’re using them at the edge (two of them in a hybrid core/edge model right now, even!) and I would happily endorse them for edge routers. Their BGP stack hasn’t put up any major roadblocks for us so far (at least, that weren’t, ahem, self-inflicted). We’ve had 1 incident in the last ~2 years where a stuck route on one router needed a full reboot to clear out, following a partial outage - that’s the worst thing I can remember right now.
Don’t know if you know this already or not, so making it clear: the one thing to beware of IMO, compared to e.g. a high-end Juniper MX960-style system where you can turn every single feature on without caring, is that the Aristas can do almost anything you can dream of… but not necessarily all at the same time on the same box, no matter which model you’re looking at.
So if you use it as an edge router? Fine. As a VXLAN gateway? Fine. As a core router or switch with every kind of accounting turned on? Fine. All of those things simultaneously? Maaaaaybe. It’ll be decision time for which specific, individual sub-features you can live without. But you’re paying 1/10th (probably less!) of what you would for an MX960, so there you go.
If this helps, they’re similar to the Cisco Nexus platform in this regard, e.g. if you enable and use every single “Feature” on the fixed-configuration Nexuses you’ll start running out of hardware configuration resources to enable them long before you can finish configuring or using all those features.
This is something your Arista SE can go through with you in excruciating detail (keyword: “TCAM Profile”), if you think you might be veering into that territory. After lots of iterations, and a new software release or two, our all-in-one boxes (7280SR2K) do more or less everything we want them to. (Apparently we aren’t typical Arista customers. Go figure.) If you want to do BGP and MLAG at the same time on the same box, get your SE involved from the start.
For anyone not trying to overload the platform or do too much “weird” stuff, it should be a quick and easy deployment producing much happiness.